The correct answer is C. supported him energetically.
To tolerate someone means to allow them to do something that you do not like or agree with, even though you may not approve of it. To face someone boldly means to confront them in a brave or confident way. To oppose someone insistently means to disagree with them strongly and continue to do so even though they may not agree with you. To support someone energetically means to help them or encourage them in a strong and enthusiastic way.
In this case, the speaker is saying that they stood up for someone when everyone else was criticizing them. This suggests that the speaker supported the person in a strong and enthusiastic way, which is why the correct answer is C.