Select the correct passive form of the given sentence.
Who killed Ravana?

Options

A. By whom was Ravana killed?
B. Ravana is killed by whom?
C. By whom Ravana was killed?
D. Ravana was killed by whom?

Explanation

(a) By whom was Ravana killed? (Correct) (b) Ravana is killed by whom? (Tense has changed) (c) By whom Ravana was killed? (Incorrect Structure) (d) Ravana was killed by whom ? (Incorrect Structure)