Select the option that expresses the given sentence in active voice.
Was the book written by an unknown author?

Correct option is D

The correct active voice of the given sentence is (d) Did an unknown author write the book?
In active voice, the subject performs the action (e.g., "The cat chased the mouse").
In passive voice, the subject receives the action (e.g., "The mouse was chased by the cat").
Explanation:
The sentence is in past simple tense and interrogative form in passive voice.
To convert to active voice, we use Did + subject + base verb + object.
Structure:
· Passive: Was + object + past participle + by + agent?
· Active: Did + agent + base verb + object?
Example:
Passive: Was the letter written by her?
Active: Did she write the letter?
�� Information Booster:
In questions, always maintain tense and question form during active/passive conversion.