From the Princeton Review:
(The preferred)A music genres of members of one generation are often (much)B (different from)C (those)D of another generation.
The correct answer is E, I chose D. I recognize this as a form of parallelism, but I thought that “those” was an ambiguous pronoun here… Help please? I’m so confused 
You are better off using real College Board materials
I don’t see any ambiguity. What word or words would you use instead? The only option I see would be to replace “those” with “the genres preferred by” but if “of” was not underlined, that’s not an option.
Thanks so much! I guess I’m reading too much into it. I thought that since it was the “music genres of members of one generation” then it would have to be parallel with “the music genres of members of another generatoin”…
Your original question is right on target. The sentence makes intuitive sense, but the grammatical sense falls apart on close examination. “those of another generation” should be read as parallel to “members of one generation,” with “those” referring to “members.” But that makes no sense. The intention of the sentence is for “those” to refer to “genres.” But the grammar doesn’t work that way.
Notice that if you remove the phrase “members of,” the sentence makes perfect sense.
It’s a broken exercise, that’s all.
It’s a very awkward sentence, to be sure.