My favorite sports is/are tennis.

Hi.

Many people say: My favorite sports is tennis. I am not comfortable with that and have looked through a lot of the old posts in this forum related to this subject, but can't come to a conclusion if it is correct to say so. I will appreciate if someone can confirm to me which of the following sentences are acceptable:

My favorite sports is tennis.
My favorite sports are tennis.
My favorite sport is tennis.

Thanks and regards.