Choose the grammatically correct option of the underlined portion given below.
Whereas the honeybee’s stinger is heavily barbed and cannot be retracted from the skin, because the yellow jacket has a comparatively smooth stinger, it is therefore able to be pulled out and used again.
The answer choices that begin with "in comparison" are totally redundant, because "whereas" already is a comparative world. Choice (D) is out.
Choice (A) has a very confused structure ---- when a sentence begins "Whereas [clause #1], ...", it sets up the expectation that an independent clause will immediately follow the comma. It is very awkward to get to the comma and find the word "because" introducing an intervening subordinate clause. Choice (A) is out.
Choice (B) seems to compare "the honeybee’s stinger" to "the comparative smoothness of the yellow jacket’s stinger" ---- not a comparison of object to object, but of object to quality of object. Furthermore, the pronoun "them" has no proper antecedent --- it appears to refer to "stinger", which is singular, but then the pronoun shouldn't be plural. Choice (B) is out.
Choice (C) constructs the comparison correctly and has no grammatical flaws. It is sleek, elegant, and precise. It is by far the best answer.