Bunuel wrote:
Although the invention of the printing press led to a significant reconceptualization of textual production in the fifteenth century, what has been equally significant in the twentieth century is the invention of the computer.
(A) what has been equally significant in the twentieth century is
(B) equally significant in the twentieth century has been
(C) no less significant in the twentieth century is
(D) what was equally significant in the twentieth century were
(E) no less significant in the twentieth century was
KAPLAN OFFICIAL EXPLANATION:
This sentence compares the invention of the printing press to that of the computer, and since the initial, nonunderlined portion of the sentence uses the simple past tense (led), the remainder of the sentence, continuing as it does to discuss a past event, must also use the simple past tense. Therefore, eliminate (A), (B), and (C) for including incorrect verb tenses. (D) and (E) give you different options for the final verb. Since the invention of the computer is the subject of this part of the sentence and is singular, the verb must be singular as well. Eliminate (D), and (E) remains.
An 800 test taker is aware that the subject of a sentence can come after the verb, particularly in constructions beginning with there are or there is.