This is bad question. The problem with it is that it attempts to draw a comparison between two nouns, but an adverb intervenes in the middle. This is a no-no on the GMAT.
Modifiers cannot jump over things they don't modify (even a ", -ing" is actually modifying the entire preceding clause). In this case, we see:
Quote:
The exhibition .... drew hundreds of people each day, MODIFIER.
The modifier is intended to draw a comparison between the number of people drawn by the exhibition and the number of people who visited the impressionist show last year. However, the frequency modifier "each day" is not part of the noun phrase involving the people; instead, it describes how frequently the exhibition "drew" people. Thus, we have:
Quote:
The exhibition .... drew (verb) hundreds of people (object) each day (verb modifier), MODIFIER
The modifier in the underlined part cannot jump over the adverbial phrase "each day" and describe the noun phrase "hundreds of people", so it must instead describe something closer. Therefore, the following comparison would actually attach to the noun "day" in the adverbial phrase. In other words, the structure forces the meaning to be that the number of days on which the exhibition drew is equivalent to the number of people that attended the impressionist show last year. This is grammatically correct, but the meaning is butchered (days compared to people).
See
this-lesson-covers-a-portion-of-gmat-pill-s-sc-framework-154137.html if you want more information.
It appears that the author of this question failed in his or her attempt to mimic an official GMAT question and the rule it tests. Only rely on questions from GMAT Prep (tests, exam pack, or question packs),
GMAT OG's (any version, including verbal), or GMAT Paper Tests. (Even those have problems sometimes, but it happens much less frequently.)