Correct Answer: Has an order for a cake been placed by you?

Solution : The correct choice is the third option.

Passive voice is the voice in which the object experiences an action rather than the person who performs the action. Hence, the object in the active sentence becomes the subject in the passive voice.

The structure of the passive voice for interrogative sentence is: " Has + object + been + past participle of the main verb + by + agent of action? "

Therefore, the correct answer will be: "Has an order for a cake been placed by you?"