Correct Answer: Am I known to her?

Solution : The correct choice is the fourth 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 sentence in the case of the simple present interrogative sentence is: "Am + singular object + past participle form of the main verb + prepositional phrase?"

Therefore, the passive voice sentence would be: "Am I known to her?"