Which of the following sentence is in Passive Voice?

Passive voice is used when the subject of the sentence receives the action of the verb. It is formed using a form of 'be' (e.g., is, was, were) followed by the past participle of the main verb. To identify passive voice, look for the structure: [subject] + [form of 'be'] + [past participle] + [by + agent, optional]. Now, analyze each option: Option A: 'My nerves are bad tonight' – 'are' is a linking verb, not a form of 'be' used in passive construction. 'Bad' is an adjective. This is not passive. Option B: 'He takes his classes punctually' – 'takes' is an active verb, and 'He' is the doer. This is active voice. Option C: 'A letter was written by him yesterday' – 'was written' is 'be' + past participle. 'A letter' is the receiver of the action. This matches passive voice structure. Option D: 'It looks good and gracious' – 'looks' is a linking verb. No action is being received. This is not passive. Thus, the sentence in passive voice is Option C.