Sentence Correction

Though most people take it for granted now, the nationwide admission of students to colleges and universities based on academic merit is a relatively recent phenomenon, beginning only after World War II.

a.Though most people take it for granted now, the nationwide admission of students to colleges and universities based on academic merit
b.Though it is now taken for granted by most people, the admission of nationwide students to colleges and universities based on academic merit
c.Now taken for granted by most people, colleges and universities admitting students based on their academic merit
d.Most take them for granted now, but the admission of nationwide students to colleges and universities based on their academic merit
e.Most people now take for granted that colleges and universities admit students nationally based on academic merit, and it

Answer - a

Please explain how "b" is wrong?

gmatlbs2015 wrote:Though most people take it for granted now, the nationwide admission of students to colleges and universities based on academic merit is a relatively recent phenomenon, beginning only after World War II.

a.Though most people take it for granted now, the nationwide admission of students to colleges and universities based on academic merit
b.Though it is now taken for granted by most people, the admission of nationwide students to colleges and universities based on academic merit
c.Now taken for granted by most people, colleges and universities admitting students based on their academic merit
d.Most take them for granted now, but the admission of nationwide students to colleges and universities based on their academic merit
e.Most people now take for granted that colleges and universities admit students nationally based on academic merit, and it

A and B: colleges and universities based on academic merit
D: colleges and universities based on their academic merit
Here, based (adjective) seems to modify colleges and universities, implying that COLLEGES AND UNIVERSITIES are BASED on academic merit.
Not the intended meaning.
Eliminate A, B and D.

C: students based on their academic merit
E: students nationally based on academic merit
Here, based (adjective) seems to modify students, implying that STUDENTS are BASED on academic merit.
Not the intended meaning.
Eliminate C and E.

Ignore this SC.
None of the answer choices is viable.
What is the source?

Source in MGMAT Prep Test