Debate refers to the fact that both parties use certain reasons or evidence to point out contradictions or errors in the other party's opinions, and to prove that their views on things or problems are correct. According to the above definition, which of the following options meet the constituent elements of the debate? ["The purpose of both sides of the debate is to point out the error of the other side's opinion.", 'The result of the debate is that both sides have the right views.', 'c. Both parties must express their opinions.', 'The opinions of both parties must be wrong.']