The eyes of the elephant seal adapt to darkness more quickly than any other animal yet tested, thus allowing it to hunt efficiently under the gloomy conditions at its feeding depths of between 300 and 700 meters.
(This question is from Official Guide. Therefore, because of copyrights, the complete question cannot be copied here. The question can be accessed at GMAT Club)
The sentence compares the ability of the eyes of the elephant seal and the eyes of any other animal tested in adapting to darkness. It says that the eyes of the elephant seal adapt to darkness more quickly than the eyes of any other animal. The sentence then presents a result of this fact using a verb-ing modifier. The sentence says that this fact allows the elephant seal to hunt efficiently under the dark conditions.
There is one error in the sentence: it compares ‘the eyes of the elephant seal’ with ‘any other animal’, essentially comparing eyes with an animal.
(A) Incorrect. For the error mentioned above.
(B) Incorrect. Same comparison error as in the original sentence. In this option, since ‘them’ has replaced ‘it’, the sentence now means that the eyes can now hunt efficiently. Well, it is not wrong to say that the eyes can hunt. So, this change from ‘it’ to ‘them’ is not an error. However, within the context, it seems preferable to say that the seal can hunt.
(C) Correct. This option corrects the only error in the original sentence.
(D) Incorrect. Same comparison error as in the original sentence.
(E) Incorrect. ‘it’ does not have an antecedent; logically, ‘it’ cannot refer to ‘elephant seal’ since elephant seal doesn’t allow the eyes to hunt efficiently.