Critics say that the government had fallen in the recent election

Dear nahid007,

I'm happy to respond.

You may find this article helpful:
Past Perfect on GMAT Sentence Correction

We know the action of falling in the recent election is the more recent action, and the announcing and allowing were earlier actions. We know that if we use the past perfect at all, we have to use it with the earlier actions. Using the past perfect for the falling is incorrect, so (A), (D) and (E) are out.

The question remains whether we need the past perfect for the earlier actions. Notice that the split in (B) & (C) is purely about this. I realize this is marked as an older official question: I will say that modern official question often do not come down to a split such as this.

The general rule is that the past participle is redundant if we can discern from other elements of the sentence the time relationship. Well, the sentence lets us know that the announcing and allowing happened "last year," which seems to indicate a time earlier than the elections. More important, the word "because" sets up a causal relationship. The announcing and allowing caused the results of the election, and therefore must precede the election in time. The order of the events is clear from all this, so the past perfect is irrelevant. I would say but the GMAT's current values, the answer would be (B). I have no idea what they deemed the answer on the paper tests.

Does all this make sense?
Mike