The correct answer is B. Frighten.
Intimidate means to make someone afraid or nervous, especially in order to make them do what you want.
Hint means to suggest something indirectly, especially in the hope that the other person will understand what you mean without you having to say it directly.
Bluff means to pretend to be confident or to have more knowledge or power than you really do, in order to deceive someone.
Harass means to annoy or trouble someone repeatedly, especially in a way that is intended to cause them to feel intimidated or threatened.
In this case, the speaker is trying to make the listener afraid of them, so that they will do what the speaker wants. This is an example of intimidation.