Select the option that expresses the given sentence in active voice.
By whom were these letters written?

Correct option is D

The correct active voice of the sentence is “Who wrote these letters?”
Active Voice: When the subject of the sentence performs the action, the sentence is in active voice.
Passive Voice: When the subject of the sentence receives the action, the sentence is in passive voice.
Explanation:
In passive voice, the structure is:
By whom + was/were + object + past participle
→ Active form becomes:
Who + past tense verb + object
Passive: By whom were these letters written?
Active: Who wrote these letters?
�� Grammar Rule:
When converting from interrogative passive to active, retain the question structure and use the appropriate tense.