IMO A...
B/w A and B, I would prefer active voice...
Option E, changes the meaning of sentence. Actual meaning is People take a notion for granted, in present days, though that notion is relatively recent....

wats the OA?

a) Though most people take it for granted now, the nationwide admission of students to colleges and universities based on academic merit ---- more clarity in the meaning.....

b) Though it is now taken for granted by most people, the admission of nationwide students to colleges and universities based on academic merit ---- admission of "nationwide students" looks different.
c) Now taken for granted by most people, colleges and universities admitting students based on their academic merit --- ambiguous Pronoun...It can refer to colleges, universities, or students...

d) Most take them for granted now, but the admission of nationwide students to colleges and universities based on their academic merit --- THEM is wrong as "the admission" is singular

e) Most people now take for granted that colleges and universities admit students nationally based on academic merit, and it --- what does this "it" refer to ambiguous

Is my process of eliminating the answers makes sense??? ...If not please do explain..This is the best i can figure out as of now...Experts plz do help...Thanks....

a) Though most people take it for granted now, the nationwide admission of students to colleges and universities based on academic merit ---- more clarity in the meaning.....

b) Though it is now taken for granted by most people, the admission of nationwide students to colleges and universities based on academic merit ---- admission of "nationwide students" looks different.
c) Now taken for granted by most people, colleges and universities admitting students based on their academic merit --- ambiguous Pronoun...It can refer to colleges, universities, or students...

d) Most take them for granted now, but the admission of nationwide students to colleges and universities based on their academic merit --- THEM is wrong as "the admission" is singular

e) Most people now take for granted that colleges and universities admit students nationally based on academic merit, and it --- what does this "it" refer to ambiguous

Is my process of eliminating the answers makes sense??? ...If not please do explain..This is the best i can figure out as of now...Experts plz do help...Thanks....

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.

Though most people take it for granted now, the nationwide admission of students to colleges and universities based on academic merit

Though it is now taken for granted by most people, the admission of nationwide students to colleges and universities based on academic merit

This question tests you on meaning issues and active/passive voice issues.

Most people take what for granted - nationwide admission or admission in general? Nationwide admission makes more sense to me. Ah and yes, compared to B, it is in the active voice.

What is the OA?

IMO: A

B is grammatically correct, but changes meaning.