Though most people take it for granted now, the nationwide admission

OA is A :

The original sentence begins with an opening modifier that correctly modifies the nationwide admission of students.

(A) CORRECT. This choice is correct as it repeats the original sentence.

(B) The use of the initial modifier in this choice is correct. However, the adjective “nationwide” is incorrectly applied to students, when it is meant to apply to the admission process.

(C) Here, the modifier is adjacent to the subject “colleges and universities,” incorrectly suggesting that colleges and universities are taken for granted as opposed to the admission process.

(D) This sentence incorrectly uses the pronoun “them” to refer to the “admission” which is a singular subject. The use of the pronoun “their” is also unclear as the antecedent could be construed to be “colleges and universities” as opposed to the intended antecedent, "students."

(E) Using the word "and" at the end of the underline makes the meaning of this sentence less clear by failing to draw an appropriate contrast between the current state of taking the nationwide admission of students for granted and the fact that it is a relatively recent phenomenon. A more appropriate word choice would be "but": "Most people now take for granted..., but it is a relatively recent phenomenon."