THe answer is A. Themselves. A reflexive pronoun indicates that the person who is realizing the action of the verb is also the recipient of the action.
I would definitely say B.) A smile because if you were just staring it may be rude or distracting to the speaker and a smile shows you are listening and absorbing the knowledge
Definitely B, slander doesn’t get your point across the way you want it to come across. the other options are all good, professional, respectful ways to voice your opinion
