Although new farm subsidy legislation is presently being considered in

Dear Shiv2016,

I'm happy to respond.

First, let's be clear about one thing. The GMAT SC is not simply a test a grammar. Instead, the GMAT SC is a test of grammar, logic, and rhetoric. The GMAT loves to punish students who focus exclusively on grammar, ignoring logic and rhetoric.

Second point: the passive voice is grammatically correct 100% of the time. Many students misunderstand this: using the passive voice is NEVER a grammatical error. The problem with the passive lies in rhetoric.
1) Last year, I taught a seminar on astronomy. = powerful, concise, direct.
2) Last year, a seminar on astronomy was taught by me. = wordy, awkward, lily-livered.
Both are 100% grammatically correct, but the first is a far more effective sentence.

It's not that the passive is always wrong or should only be used if all else fails. The passive is quite appropriate, for example, when we don't know and don't care about the doers of the action. Here, we don't know who is doing the "expecting"---those people, whoever they are, are outside of this sentence and not important to what the sentence is conveying. This is why the passive is a good choice here.

Also, notice that the passive tends to be a little more awkward if the verb is actually an "doing" verb, a verb describing some concrete tangible real world action. When I run, walk, talk, buy, sell, move, etc. I am doing something active in the world; other people can see these actions taking place. Here, the verb is "to expect," what I might call a mental verb. When I expect something, this process is taking place purely in my head: someone standing next to me may not even know that it's happening! The less "active" a verb is, the less it demands the active voice over the passive voice.

Now, let's talk about the pronoun. This is something called the "empty it" or or the "placeholder it." See:
The Empty ‘It’ on the GMAT Sentence Correction
When the real subject of the sentence is some kind of phrase or clause, such as an infinitive phrase or participial phrase or substantive clause, then one standard construction in English is:
it [verb][phrase or clause]
The word "it" in this context is not the real subject: it simply holds the place of the real subject, which follows the verb.

Here, (E) has:
. . . it is not expected to pass without significant revision.
The real subject is the infinitive phrase "to pass without significant revision." It would be very awkward to put this before the verb, so the "empty it" construction allows us to rearrange the sentence into a more elegant form.

Does all this make sense?
Mike