Bunuel wrote:
Except for one class in history and one in biology, all the student's graduation requirements have been fulfilled.(A) Except for one class in history and one in biology, all the student's graduation requirements have been fulfilled.
(B) Except for needing to take one class in history and one in biology, the student has fulfilled all of his requirements for graduation.
(C) The student has fulfilled all his graduation requirements except for one class in history and one in biology.
(D) Except for one history class and one biology class, the student has fulfilled all of his graduation requirements.
(E) Aside from the history class and biology class that he needs to take, the student's graduation requirements have all been fulfilled.
Basically a rhetorical question. The original sentence contains a passive voice, and wordiness concerning the one class. Also except for modifies the requirements for graduation.
B is incorrect because the continuous tense is irrelevant, since it modifies the student and they cannot need those 2 classes continuously.
C & D are very similar but C contains minor drawbacks. Usually, gmat indicates more than one problems in the incorrect choice to not create a huge ambiguity between choices. So they did with the C. First, the absence of the preposition
of. It is a rule of thumb in English that we should use of after all when there is a proceeding pronoun(in our case it is his). Secondly, the except modifies requirements in the choice C, while in D the student is modified. Also, C copied the wordy construction of the original sentence.
E has a verb form parallelism problem. In the first part the verb is active, albeit passive in the second part of the sentence.