Problem 15 - Olympiad

Select the sentence with the correct use of 'who' or 'whom.'

A. Who did you give the letter to?B. Whom did you give the letter to?C. To who did you give the letter?D. Whom is knocking at the door?

Correct: B

'Whom' is the object of the preposition 'to.' Rewriting as 'You did give the letter to whom?' shows the need for the object form.