The correct answer is A. censure.
Censure means to criticize someone or something severely. Praise means to express approval or admiration for someone or something. Defie means to refuse to obey or accept the authority or power of someone or something. Defame means to say or write things that are false and damaging about someone in order to damage their reputation.
Censure is the opposite of commend because it means to criticize someone or something severely, while commend means to express approval or admiration for someone or something.
Praise is not the opposite of commend because it also means to express approval or admiration for someone or something.
Defy is not the opposite of commend because it means to refuse to obey or accept the authority or power of someone or something.
Defame is not the opposite of commend because it means to say or write things that are false and damaging about someone in order to damage their reputation.