Question

who had been fined ? change the voice

Answer 1

The correct change of the voice is given below:

Whom had he fined?

Explanation

This is a subject implied case. A subject implied sentence in active-passive voice is a sentence that is passive but the subject is missing. While converting it into active we have to provide the subject from our side. This sentence is already passive(Who had been fine by him?). So we will provide the subject ‘he’ from our side. 

Important Note

Note that ‘who’ changes into ‘by whom’ and ‘whom’ into ‘who’ in changing voice