Multiple choice Directions: Change the voice of the given sentence. Who looks after our teeth? By whom are our teeth looked after? By whom our teeth are looked after? By who our teeth are looked after? By whom our teeth are looked? Reveal answer Fill a bubble to check yourself A Correct answer Explanation Option 2 is incorrectly formed as in interrogative sentences auxiliary precedes the subject.Opiton 3 has incorrect pronoun usage. We use 'whom' for the object. Opiton 4 does not have the required auxiliary.