Talk:IEEE 802.11/Archive 2

802.11 Portal is NOT a 802.1D Bridge
The section on the portal functionality of an 802.11 DS is wrong: Annex M.4 "4 Integration service versus bridging" explicitly states that the Portal and the corresponding 802.x LAN integration functionality does not require 802.1D bridging. -- Toffline (talk) 14:05, 11 June 2009 (UTC)
 * WP:BeBold -- KelleyCook (talk) 16:48, 11 June 2009 (UTC)

Hello sirs/madams Please get me some info regardingn multi-streaming modulation

Editing woes
I have just made a number of small edits to the main 802.11 page. Along the way I somehow (unintentionally) affected some other people's edits??? There appears to be some problem with either the wiki server or my workstation??? Can anyone suggest what might have gone wrong, and how I can fix it? My apologies to those whose edits were affected - that was NOT my intent. -- DarwinE 05:23, 28 January 2005 (UTC)

802.11n 540 Mbps ?
Where did this value come from? Seems questionable to me.

Mike Moreton 11n adds an additional 5/6 coding, that means you increase the maximum OFDM bit rate from 54Mbps to 65Mbps.

With 40MHz channels, you get slightly more than double because the guard bands at the sides of the channel are shared over 40MHz rather than 20MHz, which takes you to 135Mbps.

But that's one stream - four streams gives you 540Mbps. If you have very good reception!

There's also a reduced gurad interval option that takes it up to 600Mbps... -- Mike Moreton 14:06, 21 July 2006 (UTC)

Terrible writing
The third paragraph on the page is terrible (I'd edit it, but this would entail poring through a lot of other related material). Ideally, the first reference should be to ISM band regulations and refer to the FCC on a secondary basis. The FCC is not a global organization! The language and English should be improved in this paragraph as well. -- 149.135.44.84 11:48, 24 May 2007 (UTC)

No section on health effects, etc.
Could someone add a section on health effects, or at least a link to the salient Wiki article?

A BBC "Panorama" documentary raised questions that resounded around the world, e.g., on Slashdot, http://ask.slashdot.org/article.pl?sid=07/05/22/1230231 --and, of course, this is related to controversies about signals from cellular phones in general.

Another example of the genre of concerned article (with all scientific claims vaguely stated): http://www.fmlink.com/ProfResources/Magazines/article.cgi?FM%20World:fmworld071807.html —Preceding unsigned comment added by 89.243.184.205 (talk) 16:01, 19 July 2009 (UTC)

Invalid payload size
Maximum length of payload is 2312 bytes. But in this article it is mentioned as 2132 bytes. I suspect this could be a typo. Could some one verify this? Sathakselva (talk) 14:26, 15 September 2009 (UTC)
 * Clearly you were are probably correct in that it was simple transposition, but 2312 would also be misleading as that's only if you include the security extensions. So I put 2304 which is what 7.1.2 says along with the caveat. -- KelleyCook (talk) 18:03, 15 September 2009 (UTC)

Conflicting information?
In the summary it lists ranges in feet, but in the sub sections, it lists in metres, and the numbers do not even align with the summary box. See 802.11b as an example. -- 68.108.180.53 07:15, 22 August 2007 (UTC)

"WiFi generally reflects around objects rather than going through them." - removed, how do I pick up signal on my porch then? Must be a miracle huh? —Preceding unsigned comment added by 98.77.65.121 (talk) 15:32, 16 September 2009 (UTC)

Issue in Protocol version
Hi, It is mentioned that the protocol version referred as 802.11b or 802.11g. But this is wrong. As per the specification Protocol version is zero (0) irrespective of IEEE amendments (802.11b or 802.11g). I modified this and listed the sub fields in bullet.

Sathakselva (talk) 06:01, 17 September 2009 (UTC)

Frames in 802.11
This article discusses more about frame format rather than technical details. I would like to create a new article which deals about frame formats in detail. Is that ok? pls suggest? Sathakselva (talk) 08:14, 26 September 2009 (UTC)

draft n vs n
did anything significant change between draft-n and final and if so is it likely to create compatibility issues. Plugwash (talk) 20:11, 22 October 2009 (UTC)
 * Yes, the compatibility is covered in the second paragraph of the 802.11n page, but feel free to add something here also. On that page, I'll get around to adding what new optional features are tested for. -- KelleyCook (talk) 23:04, 23 October 2009 (UTC)

Summary needed
I would think that a lot of people who come to this page are here to compare the data rates of the various flavors of 802.11. I would suggest a comparison summary of the popular versions with the throughput and distance capability be placed near the top of the document.206.80.111.2 (talk) 17:57, 11 November 2009 (UTC)


 * I was thinking this:

Quick look: Common Protocol Versions

206.80.111.2 (talk) 18:28, 11 November 2009 (UTC)

Absolutely agree. The current summary is no use for most readers. I'd say go ahead with your suggestion. In fact ... I'll do it right now :-) —Preceding unsigned comment added by 70.112.150.104 (talk) 17:17, 14 November 2009 (UTC)

IEEE 802.11 vs. Wi-Fi
Based on reading the Wikipedia articles, it seems that the terms IEEE 802.11 and Wi-Fi are almost synonymous. The term Wi-Fi is applied to devices that have undergone a Wi-Fi Alliance certification process. Don't IEEE 802.11 devices also undergo certification? Are the standards being certified different? What exactly is the distinction? Is Wi-Fi just a marketing term?

In my experience, these technologies are referred to as Wi-Fi by the general population, so the distinction (or lack thereof) should be addressed in the intro. Mgnbar (talk) 14:53, 16 October 2009 (UTC)
 * The following is my undestanding of the situation:
 * Any wireless device will need regulatory certification but generally the regulators only care about basic stuff like power levels, antenna gain, leakage out of band and making it awkward for customers to connect their own transmit antennas not compliance with any particular protocol.
 * The IEEE don't certify compliance, any company can claim they follow 802.11 (of course if they claim that and don't actually do that they could get sued for misrepresenting their product but I suspect it would be a difficult case to win unless the non-compliance is gross).
 * Wi-Fi is a trademark of the Wi-Fi allegiance, so if you want to use that term for your product or service you have to follow thier rules.
 * -- Plugwash (talk) 00:52, 27 November 2009 (UTC)

FHSS in early 802.11
I've looked for 802.11 early standards and I'm almost sure that 802.11 in 1997 also had FHSS in PHY layer, not only DSSS. Does anyone agree? Alfaisanomega (talk) 16:52, 9 February 2010 (UTC)

Statements about range are arbitrary, and conflict with other articles
The listed ranges on this page are both uncited, and unhelpful. The Long-range_Wi-Fi article has references on a 173 mile 802.11b network, and that's unamplified. Amplifiers which give 20 dB of gain on the receiving end are available for a couple of hundred bucks, which (given a very low noise environment) could theoretically boost the range to ten times that, the only problem would be that you'd need impossibly tall towers for your antennas to deal with the curvature of the earth. I've personally done b and g networks with hops of over 7 miles, but seen some that wouldn't go 100 feet. It's all in the implementation.

Range can be determined by working one's way through several formulas in sequence, most of the more important ones can be found here: http://www.zytrax.com/tech/wireless/calc.htm

But giving ranges as this article does... what's the transmitter's power? The antenna design, and number of antennas? The receiver sensitivity, and noise level? etc., is kind of meaningless, and arguably deceptive. 69.110.156.71 (talk) 00:39, 16 May 2010 (UTC)

CSIRO patent
I'm a bit surprised that there's no mention of the CSIRO patent, especially as the patent application itself gives some interesting technical insights. 150.101.52.48 (talk) 03:54, 20 July 2010 (UTC)


 * CSIRO is mentioned in the Wi-Fi article. 802.11 and Wi-Fi are covering the same material. I have proposed a merge. --Kvng (talk) 14:35, 20 July 2010 (UTC)

Other protocols besides IP, IPX and Appletalk?
There is no mention in this article about the fact that only IP (and probably also IPX and Appletalk) are supported in a 802.11 network.

Reading the relevant standards documents also does not answer the question as to why this restriction is in place.

In practice, it seems that multicasts and broadcasts which do not belong to either IP, IPX or Appletalk, ARE forwarded. This raises my eyebrows even more!

Is there an expert who can shed some light on this issue?

Thanks!

BartZorn (talk) 10:41, 17 August 2010 (UTC)

on channel separation...
Surely the distance (and attenuating material) between base stations, and also the receivers, is a factor?

EG from that diagram showing the signal attenuation with frequency either side of the central one, if you have a lot of APs clustered together, you're going to have a fun time carefully setting each one to channel 1, 6 or 11 (and 14, if you're sneaky or in Japan) to avoid interference. But if they're far enough apart that there's sufficient signal drop, you can cluster closer together. Certainly, 1, 5, 9, 13 is workable. If they're even further separated, you can - quite annoyingly, as there's less point to it! - even extend that to 1, 4, 7, 10, 13. At which point you can pretty much eliminate the problem of same-channel interference.

I'm not sure how far it has to be, but certainly in my residential area (where there are a LOT of home wifi stations), I only seem to need a 1-channel separation to get a good 54g signal! (Put the AP on channel 3 and change the name to one that encourages neighbours to not use channels 2, 3 or 4) --- however, nearby stations are still strong enough to interfere and cause either serious speed loss, or total signal dropout, if they're on the same or immediately adjacent channels. Before I tweaked my AP position and aerial orientation, a 2 channel clear zone was needed (old, high-attenuation house...), i.e. put it on C4 and block out C2-6. But certainly not the case of taking C6, then having to block out C2 thru C10! 193.63.174.10 (talk) 14:00, 25 September 2010 (UTC)

 -- additional comment -- 

When designing your network, or adding a device to the home network, emphisis should be first be placed on non-interfering carrier channels, than on bandwidth separation.

Spread spectrum allows adjacent channels to share a frequency spectrum with minimal interfereance. It does this by 'hopping' the frequency to different points of the specturm faster than the information is being conveyed. Therefore it is more helpful to use different carrier frequencies (channels) and have overlaping bandwidth rather than share carriers AND all their bandwidth.

If I only have 3 transmittiers in range, the 1, 6, 11 scheme is desirable. With, say, 9 transmitters within range: two on Channel 1, four on Channel 6, and two on Channel 11; Adding my transmitter using any channel of 2,3,4,5,7,8,9,10,12,or 13 will have an apreciable performance gain. This is due to the spread spectrum's method that rejects non-cohesive signals sharing the same frequency spectrum.

I'll find a reference from my signals and systems textbook, then add it to the page someday. —Preceding unsigned comment added by 12.108.21.226 (talk) 19:01, 26 January 2011 (UTC)

Wi-Fi again
Egad, not even a wikilink to WiFi, which is the term most people (albeit not totally precisely) use for this family of technology? The split between the two articles makes sense, this one for IEEE technical standard and that for the trademark. But not even mentioning it here, let alone a short explanation of the relationship is quite odd. Any reason for this? W Nowicki (talk) 17:26, 9 June 2011 (UTC)
 * Or did you mean Wi-Fi, which is linked in the body of the article, and now the lead? --Wtshymanski (talk) 18:02, 9 June 2011 (UTC)

You are right, the dash seems precise, and thanks for stating what seems accurate: that these are the standards and Wi-Fi is the product name. That was quick. W Nowicki (talk) 21:46, 11 June 2011 (UTC)

Merge from Regdomain
Regdoman is a one-paragraph definition that might be better here in this article to give it context. --Wtshymanski (talk) 22:12, 14 November 2011 (UTC)

The modulation of 802.11ac is OFDM, same as 802.11n
This post is in reference to the table below the topic "Protocols" and specifically to the column labeled 'Modulation'. The 802.11g, n, and ac protocols all use OFDM as a modulation. They also all use QAM encoding to obtain multiple bits per symbol on each OFDM subchannel. The change in the column from OFDM for 802.11n to QAM for 802.11ac is misleading. I think that instead all references to OFDM in that column should read OFDM - QAM as they are both properly referred to as modulations.

This change was made on 1/27/2012.

Halichopter (talk) 16:02, 27 January 2012 (UTC)

802.11ac speeds in table are not using the same "data rate per stream" as the other IEEE protocols
Whereas 802.11n correctly calls out a max rate of 150Mbps per stream. The rates in the 802.11ac aggregate bandwidth from all of the streams. — Preceding unsigned comment added by Halichopter (talk • contribs) 02:08, 29 January 2012 (UTC)

Why commerce with Cisco / Linksys on 802.11 page?
Why commerce with Cisco / Linksys on 802.11 page? — Preceding unsigned comment added by 80.203.128.66 (talk) 10:44, 19 March 2012 (UTC)

standard release timeline
The page states that 802.11a was released before 802.11b. While it's true that work on creating the 802.11a standard began first, 802.11b was actually released first. If you need a source for that information, I got it from Tamara Dean's Network+ Guide to Networks, 5th Edition, published by Course Technology, Cengage Learning in 2010. Khylaria (talk) 23:14, 17 March 2013 (UTC)Khylaria

Maximum speed
802.11n: "It operates at a maximum net data rate from 54 Mbit/s to 600 Mbit/s." This is a range, not a maximum. What is the maximum speed? or are there multiple maximum speeds, depending on certain circumstances and what are those circumstances? — Preceding unsigned comment added by 124.191.112.66 (talk) 22:12, 5 November 2012 (UTC)

The "certain circumstances" include things like which frequency is being used at the time, and whether or not the network is a "mixed environment" - meaning more than one standard being used in the network. For instance, if you have a completely 802.11n network, you'll be able to reach those 600 Mbps speeds. However, if you have 802.11.a/b/g equipment, network speed will be reduced to the slowest standard on the network. The maximum speed for 802.11n with 802.11g equipment on the network is 54 Mbps; with 802.11b equipment on the network it's 11 Mbps; and with 802.11a equipment on the network it's 54 Mbps. Khylaria (talk) 23:31, 17 March 2013 (UTC)Khylaria

Actually, it is a range of maximum speeds. 802.11n offers basically three options: channel width, nbr of spatial streams and guardtime. Depending on the options implemented on the AP and the client, the theoretical maximum speed varies. Example: (20 MHz/1 stream/800ns) -> max 65 Mbps, (20 MHz/1 streams/400ns) -> max 72.2 Mbps upto (40 MHz/4 streams/400ns) -> 600 Mbps. Be aware that these raw maximum speeds are including coding overhead and the uplink and downlink rates are added up.

Inaccuracies
This page has many inaccuracies and is out of date. I'd suggest you put a heading to indicate this. — Preceding unsigned comment added by 202.129.82.218 (talk) 07:19, 19 June 2013 (UTC)
 * Even better would be to say what in particular you think is inaccurate or out of date. Thanks. W Nowicki (talk) 19:51, 19 June 2013 (UTC)

on channel bandwidth
As far as I know, the channel bandwidth in DSSS is 22 MHz (11 Mchips/s). The same channel structure is used for 802.11a and g (which mainly use OFDM modulation scheme). Thus, do not you think that in the table "protocols" we should put "22 MHz" on channel bandwidth OR "20 MHz (nominal bandwidth)"?. This last one could be appropiate, since the standard uses the term "channel spacing" for this issue. Waiting for your responses to edit the article.


 * It's 22 MHz for DSSS (b, or certain modes of g) as you say, but 20 for OFDM (a and g). Perhaps we could add a distinction between bandwidth use and channel use? Teslacuted (talk) 00:32, 16 July 2013 (UTC)

14th channel
Article currently says "The 2.4 GHz band is divided into 13 channels spaced 5 MHz apart, beginning with channel 1 centered on 2.412 GHz. A 14th channel was briefly proposed in Japan, but later dropped.[citation needed]"

However the 2007 and 2012 rollups both reference channel 14 in the channel maps (search for '2484' -- its frequency). I'm rewording this section to make it clear that the channel exists but is limited to certain regulatory domains.

Teslacuted (talk) 01:41, 16 July 2013 (UTC)

Hobgoblin of little minds
This page says clearly:


 * 802.11g was based on OFDM modulation and utilized a channel bandwidth of 20 MHz. This occasionally leads to the belief that four "non-overlapping" channels (1, 5, 9 and 13) exist under 802.11g, although this is not the case.

And the diagram:

seems to show the non-overlapping channels as 1,6 and 11, like 802.11b

But the diagram: which is also included shows the non-overlapping channels for 802.11g/n as 1,5,9 and 13, in direct contradiction of the article.

So, what is it? HughesJohn (talk) 12:46, 11 August 2013 (UTC)


 * According to the 2007 revision, in section '19.5.2 Adjacent channel rejection' "Adjacent channels at 2.4 GHz are defined to be at ± 25 MHz spacing.".


 * My reading of this is that even though this was originally based around 22MHz carriers when using CCK, the OFDM modulation reused the spacings without redefining them, which I imagine would have required a full channel->frequency reassignment. So, as the centre frequencies of the OFDM carriers are at the same frequency as a CCK carrier, they are still technically adjacent to each other, even though their nodes fall off faster than a CCK carrier. Technically adjacent, therefore technically no change to the non-overlapping channels. However I imagine that if OFDM only operation could be guaranteed the 1,5,9,13 scheme could be considered valid, but since the rate selection is automatic, a station can dynamically switch to CCK (or worse, Barker) if its SNR is too low, which means you can't really, practically, ever guarantee OFDM only operation. This means the red-on-white diagram is technically correct (the best kind of correct) but it doesn't make it clear that the same network may be using multiple modulation rates at the same time. Management frames, in particular, are often sent at an older modulation, even in good SNR environs.


 * This is of course, all wild speculation and should be treated as such. Teslacuted (talk) 19:49, 11 August 2013 (UTC)

I don't understand "This occasionally leads to the belief that four "non-overlapping" channels (1, 5, 9 and 13) exist under 802.11g, although this is not the case.". Why are they overlapping? The PSD shape is 18 MHz wide and drops at the edge in 2 MHz by 20 dB. — Preceding unsigned comment added by 135.245.192.4 (talk) 15:56, 6 November 2013 (UTC)

802.11-2012
The Standard or amendment? subsection of the Standard and amendments section seems to have been missed when updating the article with respect to 802.11-2012 — ~Bin~talk 09:36, 19 April 2012 (UTC)

Agreed. There is more information on the new IEEE 802.11ae-2012 standard on the IEEE website: https://standards.ieee.org/findstds/standard/802.11ae-2012.html 10:38, 7 May 2012 — Preceding unsigned comment added by 50.15.136.118 (talk)

Colleagues. I have reviewed the new 802.11-2012 standard (IEEE released it to the 'GET' program just yesterday). There are so many new additions (and changes), that I believe it deserves it's own article -- so I created an initial draft. If you care to review and/or expand upon it, please examine it here: http://en.wikipedia.org/wiki/Wikipedia_talk:Articles_for_creation/IEEE_802.11-2012 — Preceding unsigned comment added by Paul.j.richardson (talk • contribs) 16:49, 2 October 2012 (UTC)
 * Looks like a good start to me. ---fudoreaper (talk) 07:34, 4 October 2012 (UTC)

In Standard and amendments you find a lot of 802.11 protocols, in section Protocols only the main protocols a,b,g,n and new for me 802.11-2007. I like the table in Protocols, so is it possible to merge this two sections?194.113.154.132 (talk) 14:52, 1 October 2013 (UTC) br


 * I don't understand why this very important start on an article is being rejected by Wikipedia. Does Wikipedia no longer allow stubs?  If so that seems like a very bad move by Wikipedia.  Vaughan Pratt (talk) 00:20, 22 August 2014 (UTC)

More confusion in the paragraphs about channel separation
The 3 paragraphs about channel separation, which begins with "Confusion often arises..." seem to be confused themselves. Most notably I see two issues in the current text, but am not sure how to fix it, as I do not know the facts well enough. The two issues are:


 * There is an unfortunate conflation of the rules for assigning channels to multiple (cooperating, roaming) access points (cells) of a single large network/SSID and the (different) rules for assigning channels to multiple networks/SSIDs where the access points don't talk to each other, but the (human) owners try to minimize mutual interference. Similarly, there is some conflation between what happens if you line up all the conflicting access points on a small table in the middle of the house and what happens when each access point is in a different home/office in a large crowded building.  The Villegas source discusses these distinctions, but with little detail.
 * A Cisco article about the inadvisability of using 15MHz channel separation for multi-cell networks in the US 11-channel regdomain is used as the sole source for a claim that 20MHz channel separation is problematic in the EU 13-channel regdomain, while a research article that used spectrum analyzers to scientifically investigate how much channel separation is really needed is used as the sole source for a claim that such high end equipment is needed to decide if 20MHz separation is good enough for each real world situation. That badly sourced paragraph contains important information which should be given (after adjusting for factual correctness), so it cannot simply be deleted, but it needs to be fact checked then the facts need to be properly sourced. Jbohmdk (talk) 01:26, 13 September 2014 (UTC)

Article does not meet Wiki standards
Wireless N redirects here. About.com says: "Answer: Wireless N is a name for hardware gadgets that support 802.11n Wi-Fi wireless networking."

This article seems too technical and full of jargon, which is another way of saying it's poorly written. Wiki guidelines require that articles be accessible to the average user (IMO; at least in the lead section). Duh. It describes a bunch of rules but does not explain what the hardware gadgets do, what such a device is called, what purpose these devices serve, etc. The Big Picture. Suggest looking at some other sources such as perhaps: What Is Wireless N? or youtube's Wireless G vs N explained for suggestions to better explanations. See also: Manual of Style (lead section). Please remember that a list of facts is not an explanation. A list of parts does not describe a car nor any other system. Thanks. --108.252.225.238 (talk) 04:07, 17 July 2014 (UTC)Doug Bashford


 * This article covers the facts in much more details than the blather in sales brochures. As a reasonably educated person I generally prefer details to oversimplification.  It explains not only Wireless a, b, g, n and ac, but also the lesser known letters used, as well as the bigger picture and some issues that real world people have to deal with to use the related "gadgets".  Please keep this article as a detailed overview of the whole 802.11 standard family, don't dumb it down to beautifully written sweet nonsense.  If I look up Elephants I also expect something much more detailed and precise than "huge gray animal with very long nose that it can move like an arm and two very long white teeth". Jbohmdk (talk) 01:47, 13 September 2014 (UTC)

Need definition for UDP
In the section Common Misunderstandings (https://en.wikipedia.org/wiki/IEEE_802.11#Common_misunderstandings_about_achievable_throughput), the term UDP is used a few times yet never defined. Looking up the WP article on UDP (https://en.wikipedia.org/wiki/User_Datagram_Protocol) gives no understanding.

Can someone with detailed knowledge please address this issue?

Thanks, WesT (talk) 17:04, 9 April 2015 (UTC)


 * The definition of UDP here is, indeed, an initialism for User Datagram Protocol. Presumably what you need is an explanation of something here; what needs to be explained? Guy Harris (talk) 17:38, 9 April 2015 (UTC)

Dubious
The article appears to have omitted important information relating to how MAC Addresses appear in the 802.11 frame "An 802.11 frame can have up to four address fields. Each field can carry a MAC address. Address 1 is the receiver, Address 2 is the transmitter, Address 3 is used for filtering purposes by the receiver."

From my limited knowledge of the 802.11 standard the above address representations are usually correct, however if the message is being transmitted over a Distributed system (as defined in the ToDS and FromDS bits of the Frame Control field), the above statement is incorrect. This explains why the article shows four address fields but only explains three, as the forth field is used to represent the source of transmission only when the ToDS/FromDS fields are set.

The following site explains this, and is frequently referenced by students taking their Cisco certification so it would appear reliable.

I apologise in advance if any part of raising this is not up-to the wiki standards, I rarely edit on Wikipedia and therefore have tried my best to raise this in a constructive manner. I currently do not have the time to correct this section myself and as you can probably tell I am not brilliant at using the Wiki markup, this may change in the near future if I manage to get a day off work.

Let me know if you need anything else from me.

Thanks — Preceding unsigned comment added by SirkusSystems (talk • contribs) 15:39, 14 December 2015 (UTC)

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