= This is my 1000th post == My answer is
(B). It took me 01:36.
Note that (B) is the only option that uses past perfect tense in "class war that
had been predicted never took place". The prediction of the class war occurred before the fact that such prediction failed to materialize. In my opinion, the use of past perfect tense is not only appropriate but also essential.
To be on the safe side, though, I still wanted to check if there are other issues with the remaining options.
Options (ACE) uses Cleft Sentences: It for emphasis. Per
https://www.thoughtco.com/adding-emphas ... m%20crazy., Sentences introduced by 'It', such as 'It is' or 'It was', are often used to emphasize a specific subject or object.
(C) does not correctly use this structure because "that" should be used in the place of "which".
For (AE), we need to ask if the emphasis on the two main political parties is warranted.
If the sentence for (A) started with "Despite the fact that myriad parties were involved in the volatile cataclysmic class war", the emphasis on the two main parties would make more sense.
Likewise, we can rewrite E to be more acceptable. "The volatile cataclysmic class war saw numerous players, but ..."
However, when the first part of the sentence talked about a volatile war that did not take place, it is bewildering to read the emphasis. Such writing leaves readers guessing the purpose of the emphasis: Did the two main political parties have anything sinister to do with the failure for the predicted war to happen? Did they collude to quash other parties to avert the war that would otherwise have taken place and changed the political landscape in which the two parties would no longer be the dominant players? The sentence does not provide enough evidence to suggest the need of the emphasis.
As for (D), the use of "whereas" suggests strong contrast between two clauses. The two clauses should be connected to the same theme. (Tom is a fan of classic music whereas John enjoys k-pop.) In (D), the two clauses are only loosely connected at best.
So, if we believe the past perfect tense must be used, (B) is no brainer. Otherwise, we have to discern many subtle distinctions.