The answer to the blank space is (C) negotiating a situation.
When you’re confronting someone, you need to ensure that a consensus is reached between the two of you and the situation is not exacerbated.
You should refrain from bringing supporters because this would make the person feels cornered. Though making sure you’re right is important, confronting someone just to prove that you’re right would only lead to a stalemate situation if the person is not willing to back down either. Listening to rumors would only cause problems for you if what you heard is false.