The mathematical concept of "zero" was born not

A quick scan of the answer choices reveals two basic alternatives—"was born not" and "was not born." We eliminate (A) and (B) because "was born not" is not parallel to but evolved. The two verbs are being balanced by not and but. (B) also uses the passive "was evolved" which is an incorrect use of the word "evolve".

(D) unnecessarily adds the word "it." This could only be correct if the form of the sentence were ". . . was not born in a sudden moment of revelation; rather, it evolved slowly . . ." Since that is not the form used here, the word "it" is not needed.

(E) incorrectly uses the past perfect tense "had evolved" because the past perfect is only necessary to compare a sequence of events in which one event precedes another event in the past. Here, there is no sequence of time—the whole sentence is in the same past time.

(C) uses the proper "was not born" parallel to "but evolved" and the proper simple past, active form "evolved".