Please check the below post,

https://www.manhattangmat.com/forums/gma ... t7187.html

Firstly, you did a good job to boil it down to A, B and C. From this perspective, it is important to note that:

1. D and E use which, which cannot in any way modify Television costs, the intended referent.

2. A, B and C use Appositive modifiers, which are handy when the intent is to modify the entire clause.

For choices between A, B and C:

A-> it (singular) cannot refer to television costs (plural), the intended referent. was is also an issue, since was cannot elide for "accounted for". did would have been a better choice.

C-> they refers to Soaring television costs, while the intended referent is television costs. have been is also problematic, since have been accounted doesn't fit here.

EducationAisle wrote: A-> it (singular) cannot refer to television costs (plural), the intended referent. was is also an issue, since was cannot elide for "accounted for". did would have been a better choice.

I interpreted the referent of it as greater proportion, the subject of its own clause; in that case the subject and the verb agree and was can correctly replace proportion in any previous election was. Please let me know what is wrong with my interpretation.

Thanks for you response.

Well, greater proportion for it would not make sense (try substituting: a greater proportion than greater proportion was in any previous election).

Lets step back a bit and phrase the ideal sentence (This always helps in ellipsis):

Soaring television costs accounted for more than half the spending in the presidential campaign of 1992, a greater proportion than (proportion) in any previous election.

The above ideal construction is the reason why choice B is correct (proportion is elided).

Notice that a greater proportion than (proportion) in any previous election is not a clause, its a phrase (Appositives are phrases). However, it was in any previous election, in the original sentence is a clause and so, we were looking for its referents in the previous clause: Soaring television costs accounted for more than half the spending in the presidential campaign of 1992. television costs was perhaps the intended referent, but it (singular) cannot refer to television costs (plural).

The following would perhaps have been better:

Soaring television costs accounted for more than half the spending in the presidential campaign of 1992; the proportion was greater than it was in any previous election.

Now, we can identify it referring back to proportion.

Thanks for the terrific explanation Ashish (EducationAisle)!