who is used to ref to Human Being only. & of which vibrate to cause roar is not logical in E.

its between A & B.
its is wrongly used in option A>

B is best fit.
_________________

I don't think you can use 'who' to refer to animals.
_________________

OFFICIAL EXPLANATION

The original sentence incorrectly says "can be roaring", when the appropriate present-tense verb form is "can roar". The sentence also makes the mistake of using a singular possessive pronoun ("its") to refer to a plural antecedent ("lions and tigers").

(A) This choice is incorrect as it repeats the original sentence.

(B) CORRECT. This choice corrects the verb problem in the original sentence by replacing "can be roaring" with "can roar". This choice corrects the pronoun problem by using the plural possessive pronoun "their" instead of "its".

(C) This choice incorrectly uses "who", instead of "which", to refer to lions and tigers. On the GMAT the pronoun "who" is reserved for human beings; animals and things are referred to using "which". Another mistake in this answer choice is the inclusion of the redundant word "differently".

(D) This choice makes the mistake of using a singular possessive pronoun ("its") to refer to a plural antecedent ("lions and tigers").

(E) This answer choice illogically makes it seem as if the hyoid bones of lions and tigers vibrate, and thereby create roaring sounds, independently of whether the lion or tiger actually wants to roar. The use of the singular "a roar" is also inappropriate, because it appears to suggest that many lions and tigers collectively emit just one roar.
_________________