Look at the underlined part of each sentence. Below each sentence are given three possible substitutions for the underlined part. If one of them is better than the underlined part, mark accordingly on the Answer Sheet. If none of the substitutions improve the sentence, mark (d) on your Answer Sheet.
By the time he arrived, everybody had gone home.

Options

A. when he arrived
B. at which he arrived
C. by which he arrive
D. No improvement