Pick out the correct sentence in passive voice of the following sentence: 'We compelled the enemy to surrender'.

While converting from active to passive voice, the positions of the subject and the object are swapped, but the tense of the sentence remains unchanged. The subject in the given sentence is 'we'. The object in the given sentence is 'enemy'. The verb in the given sentence is 'compelled', followed by 'to surrender'. The correct passive form of the sentence, therefore, would be: The enemy was compelled to surrender by us. Option D is the correct answer.