Source GMAT Prep 1:

The hognose snake puts on an impressive bluff, hissing and rearing back, broadens the flesh behind its head the way a cobra does, feigning repeated strikes, but having no dangerous fangs and no venom, eventually, if its pursuer is not cowered by the performance, will fall over and play dead.

A broadens the flesh behind its head the way a cobra does, feigning repeated strikes, but having no dangerous fangs and no venom,

B broadens the flesh behind its head the way a cobra does and feigns repeated strikes, but with no dangerous fangs and no venom,

C broadening the flesh behind its head the way a cobra does and feigning repeated strikes, but it has no dangerous fangs and no venom, and

D broadening the flesh behind its head the way a cobra does and feigns repeated strikes, but with no dangerous fangs and no venom, and

E broadening the flesh behind its head the way a cobra does, feigning repeated strikes, but with no dangerous fangs and no venom, and


How to choose b/w C, D and E?

Is it E?

I vote for E as well. The snake will put on a bluff and will eventually fall over and play dead.

Within the modifier, "feigning" needs to be there.

Only question is the
"but with no dangerous fangs and no venom,"
who/what is it modifying. What is it doing there ?

Anyway I vote for E, even though I don't understand the part above.

It should be C. This choice has better parallelism than does choice E, and is phrased in a way that makes MUCH more sense. Choice E, while not strictly ungrammatical, is a 'garden path sentence' - one that reads incorrectly the first couple of times your eyes run over it, and that only makes sense if you go back and read it several more times. The specifics:

C:
The hognose snake puts on an impressive bluff,
hissing and rearing back, broadening the flesh behind its head the way a cobra does and feigning repeated strikes, --> note the parallelism between these two parts: both are in the form '(verb)ING and (verb)ING'

but it has no dangerous fangs and no venom, and eventually, if its pursuer is not cowered by the performance, will fall over and play dead. --> contains a key transition ('but'), and the start of a new clause (new subject & new verb), in just the right place - to mark the sudden transition/contrast between the stuff in the first half (all this intimidating behavior) and the stuff in the second half (it's all a big fake - snake oil, if you don't mind the pun).

E:
The hognose snake puts on an impressive bluff,
hissing and rearing back, broadening the flesh behind its head the way a cobra does, feigning repeated strikes, but with no dangerous fangs and no venom,
These two items are falsely made to look like two more items in a series begun with 'hissing...' and 'broadening...'. In addition, there is NO emphasis on the transition 'but', because no new clause is begun at this point. That's bad, because there's a sudden huge shift in what the sentence is talking about at this point.
and eventually, if its pursuer is not cowered by the performance, will fall over and play dead.

Oh yeah, I forgot to add: Choice D has terrible parallelism between 'broadening' and 'feigns', so it's out of contention.

In the above sentence why can we not take the below verbs as parallel, why is B incorrect ?

The hognose snake puts on an impressive bluff, hissing and rearing back, broadens the flesh behind its head the way a cobra does, and feigns repeated strikes, but with no dangerous fangs and no venom, eventually, if its pursuer is not cowered by the performance, will fall over and play dead.

The only logical reason I can think of is in "C" After "But" the word "it" is used to reinforce the subject.. but is B gramaticaly incorrect ?

Thanks

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the meaning of the sentence clearly indicates that the forms of broaden and feign should be parallel to "hissing and rearing", since all of those things are actions that occur during the "impressive bluff".
you can't choose which verbs are parallel at random! if you have verbs that are logically parallel, then you must make those verbs grammatically parallel as well to do anything else is to distort the meaning of the sentence.

I just wonder whether an "and" is missing between "hissing and rearing back" and "broadening the flesh behind its head the way a cobra does and feigning repeated strikes".
Or a series of adverbial modifiers that appears in the middle of a sentence doesn't require any conjunction?

time to rescue my post before it sinks to the bottom ;-)

from this problem, we learn the answer: 'apparently not'.
in other words, no such 'and' is needed.

remember, we don't make the rules; they do. if you notice a certain construction used IN A CORRECT ANSWER, you can rest assured that that particular construction is, indeed, grammatically viable.
they're a bit weird sometimes, but at least they're consistent.

also, remember that, ultimately, the gmat is the only authority that matters when it comes to grammar. if you find other sources that disagree with this sort of usage, it doesn't matter - the test writers make the final call.

Apart from the parallelism which is set by hissing and rearing, the usage of "it" after but provides clarity to the sentence.

In other choices "but with no dangerous fangs and no venom" lacks a verb and therefore sounds off.

Good point, manicchamp.

"with no dangerous fangs and no venom" is a prepositional phrase, which could either be a noun modifier or adverbial modifier. A couple of examples:

Noun modifier: The snake with no dangerous fangs and no venom would make a nice pet.
Adverbial modifier: The snake struck with no dangerous fangs and no venom, so we decided we could tolerate him as a pet.

The fact that this phrase could modify either a noun or a verb or a phrase makes BDE very ambiguous.