Answer:A. Do not heckle
Explanation: Heckle means you disrupt someone by yelling annoying or rude things and comments.
This is unethical because you every speaker deserve a chance to actual deliver their speech and the audience have the responsibility to actual listen to the speaker with an open mind. This means that you can't tell at someone because you don't agree with their point of view but you have to be open minded enough to understand their point of view and without insulting them you can also get your point across in a polite way.