Free Grammar Help — Quiz 5 — Who or whom?

Choose "who" or "whom" for each question. When all questions are answered, click at the bottom of the page to see your score.

Do not seek to know for who/whom the bell tolls.
I don't know who/whom to ask to the dance.
Who/Whom is responsible for this mess?
You don't know who/whom you're talking to!
Jack asked who/whom he should give the letter to.