Unlike an oboe and clarinets, which are subject to built-in obsolescen

Here's the official explanation provided by the GMAC for this question:

The sentence contrasts bassoons with oboes and clarinets with respect to durability. In the given sentence, the use of the preposition unlike is correct, but the singular an oboe is rhetorically inappropriate in that it is nonparallel with the plural nouns bassoons and clarinets. Each plural is intended to refer to a general class rather than to a single instance of the class. The indefinite article is also commonly used to refer to a general category; however, an oboe would be appropriate only if the other categories were referred to similarly: Unlike an oboe or a clarinet, each of which is subject to … a bassoon can last indefinitely. The phrase Unlike an oboe and clarinets, though flawed in the way explained, functions as an adverbial modifier of the verb last.

Option A: This answer choice fails for the reasons explained.

Option B: Correct. All three nouns referring to general classes are plural as required. The phrase unlike oboes and clarinets is an adverbial modifier of the verb last.

Option C: The phrase different than oboes and clarinets must be read as an adjectival modifier of bassoons. In context, however, the truism that bassoons are different from oboes and clarinets fails to precisely convey the meaning intended—that the dissimilarity relates to a difference in durability.

Option D: The singular a clarinet is inappropriate in that it is nonparallel with the plural nouns bassoons and oboes.

Option E: This is an adjectival phrase modifying the noun bassoons. In context, however, the truism that bassoons differ from oboes and clarinets fails to precisely convey the meaning intended—that the dissimilarity relates to a difference in durability.

The correct answer is B.

Please note that I'm not the author of this explanation. I'm just posting it here since I believe it can help the community.