Sir asked me if I . . . . . . mischief in the class. A. am making B. is being made C. was made D. was making

The correct answer is D. was making.

The sentence is in the past tense, so the correct verb form must also be in the past tense. The other options are not in the past tense.

A. am making is in the present tense.
B. is being made is in the passive voice, which is not typically used in conversation.
C. was made is in the past tense, but it is the simple past tense, which is used to talk about completed actions. In this case, the speaker is asking about an action that was in progress at the time of the question, so the continuous past tense (was making) is more appropriate.