Select the correct passive form of the given sentence.
The police beat a number of protestors last night.

Options

A. A number of protestors were being beaten by the police last night.
B. A number of protestors had been beaten by the police last night.
C. A number of protestors has been beaten by the police the night before
D. A number of protestors were beaten by the police the night before

Explanation

(d) A number of protestors were beaten by the police the night before. (Correct) (a) A number of protestors were being beaten by the police last night. (Tense has changed) (b) A number of protestors had been beaten by the police last night. (Tense has changed) (c) A number of protestors has been beaten by the police the night before. (Tense has changed)