would choice c be correct if the second half was changed to 'both from' or is 'being implicated' not a correct idiom?

Methane, which has long been counted among the green house gasses that are implicated in global warming, comes both from natural sources such as bogs and from a host of human sources, including coal mines, leaking pipelines, landfills, and rice paddies.

a. same
b. that are implicated in global warming, coming from both
c. being implicated in global warming, comes from both
d. implicated in global warming and coming both from
e. implicated in global warming, that come both from[/u]

Is the OA "A"?

choice c would not yet be correct, because, as you rightly suspected, 'being' is still considered awkward/wordy. in fact, 'being' would serve NO grammatical purpose whatsoever in the sentence that would thereby be constructed (it would mean the same thing if you took out 'being') - and functionless words are a big no-no on the gmat.

pretty much the only time you should accept 'being' is when it's part of a passive-voice construction, or when it's the actual action of the sentence (the main verb or verbal). if 'being' is used to say that X is Y, as it is here, you can be almost positive that it's just fluff (and that it kills the answer choice).

How is the verb form in the sentence plural? Isnt the subject of the sentence Methane - singular?

The verb in the sentence is not plural. The conjugation of the verb to come in the singular form is "comes"

She comes over everyday.
The ball comes close to me.
They come and go whenever they please.

Also there is one more error in 'c' - come from both is not correct. both from.....and from.... is correct. Hence, A is the ebst choice.

GMAT Fever, if you were referring to the verb "are," it agrees with its subject "gases." Otherwise, the singular verb "comes" does correctly agree with the singular "Methane" as Guest wrote.

Rey thanks for the response, that was what I was referring to and now that makes total sense. So is it the rule of thumb when a clause is started with "that" or any other words (i.e which, etc) the preceding noun should be the basis for the next immediate verb? (As in this case gases that are)

Also should we keep a look out for the main subject which is being modified by a clause and locate the proper verb tense that is associated with it?
(As in this case Methane,........,comes)

If you can suggest your advice on the best approach for SVA with clauses/phrases that would be greatly appreciated it.

Thanks!

friends, so what is the OA?

cheers

what is the official answer..thanks..good post

the best choice here is (a), although, if this is actually a gmatprep problem, i'm a bit surprised at the use of "that are" in that answer choice. ("that are" can be clipped without introducing any ambiguity, and we all know how the gmat feels about wordiness.)

that's a good starting rule.

alas, unfortunately, life is rarely as simple as we like to make it. indeed, this particular rule of thumb has its exceptions, too.
if you have the og11, take a look at #50 in the diagnostic test (in the front of the book - NOT #50 in the normal sentence correction section).
in that problem, there's a comma-less "that" modifier (...that will protect...) that is nowhere near the noun it modifies. the rationale is that there's really no way to reconstruct the sentence in a grammatically valid an unambiguous way so that the modifier is directly next to that noun ("way"), so we have to settle for the ostensibly "wrong" placement.

but in the vast majority of cases, yes, this simple rule of thumb will bring good results.