Patrick's analysis is on point! But I want to contribute to this question a bit more as well.
I think what makes this question hard is, first, the fact that it being a "inference" question, it tend to be the hardest in the set, because they usually require a thorough understanding of the whole passage and the author's attitude, etc. Second, specifically to this one, I think many test takers will
overthink about what the question is asking here.
As patrick has mentioned, the question specifically ask us the relationship
between the three styles.
On first sight I was like, okay, what relationship......it seems pretty natural, at least for Schoenberg, to develop these three styles.
You can tell this in paragraph 5, the author keep mentioning how Schoenberg"felt that he was a man of destiny", how these changes are"the next inevitable step in the historical development of music", in developing his styles, he "did what he was compelled to express". (Line 33-38) Although this is laid in the fifth paragraph, after the discussion from the change from the first to the second style, it is obvious that in the author's eye, these changes of Schoenberg is pretty
consistent.
Also, there seems to be nothing specifically talk about how the first one differs from the second one, or how the second one differs from the third one.
So I chose A at first, pretty unsure, because I think if this is truly how easy this question is, what about answer choices C,D and E? (And here is where the overthinking begins......). I turned around to the three paragraphs, somehow holding the thought that there must be something I have missed in the first round, and found in line 40, "......bringing a
new system of order..." and thinking, okay, that must be it, it must be that the third style is different from the second! As a result I change my answer to the wrong one, answer choice C.
Enough about the stupidity. What's wrong about this thinking?
First of all, one single word("new") does not compare to a whole preach from the author, telling us how "inevitable" it was for Schoenberg to go through these changes. (But sometimes certain vital words can twist the whole attitude to another direction, in RC passages).
Second, what is the "new" thing that the author is talking about here? It's specifically talking about the 12-tone technique(line 39)! The fact that a single new technique has been added to a piece of music does not represent "an inexplicable departure from the previous one".
Still, the transformation is consistent and inevitable for Schoenberg! (line 43-45, "as his career progressed, his music became more condensed, more violent......") . It is a consistent progression through and through.
I hope my true experience on overthinking this question to be helpful to you guys so you don't make the same mistake!
(Schoenberg's music is truly difficult...... I kinda feel sympathetic for the critic in the first paragraph.)