GMAT Sentence Correction (SC) | Although he is as brilliant as, if not more brilliant than, many of h

Although he is as brilliant as, if not more brilliant than, many of his fellow students, he is very lazy and his thesis will be unfinished.

(A) Although he is as brilliant as, if not more brilliant than, many of his fellow students, he is very lazy andhis thesis will be unfinished.
(B) Although he is as brilliant as, if not more brilliant than, many of his fellow students, he is very lazy withhis thesis remaining unfinished.
(C)Although he is as brilliant as, if not more brilliant than, many of his fellow students, he is very lazy and will not finish his thesis.