You are answering a USMLE-style medical question. Question: A 19-year-old man in a 3-month relationship with a woman experiences frequent sexual fantasies about male coworkers. He lives in a conservative community and does not know any openly gay men. Two days ago, he joined a local group considered by many organizations to be a hate group. Together with the other members, he attacked a gay couple on their way home from dinner. Which of the following psychological defense mechanisms is he demonstrating? Options: A) Sublimation B) Reaction formation C) Intellectualization D) Projection Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.