5lb Verbal (text completion) question

[jungjongyun83]

Hi,

Anybody can help on this problem?
I was trying to understand between apologist and proponent in the question of #13 from 5lb Manhattan problem book.

The question is as below:

She was not the only i)_____ of the long-proposed legislation, but she was the ii)______who finally got the bill onto the legislative agenda.
Blank (i) a. apologist b. critic c. proponent
Blank (ii) d. catalyst e. mercenary f. lackey

The answer is c and d. I chose "a" instead of "c" for the first blank.

I thought "apologist" and "proponent" are synonym.
Any help for the first blank is really appreciated.
Thank you.

[tommywallach]

They pretty much are...but apologist takes the preposition "for," not "of."

-t