You are answering a USMLE-style medical question. Question: A 23-year-old man presents with sudden loss of consciousness while pitching in a baseball game. There is no history of injury. Consciousness is regained after cardiopulmonary resuscitation. Past medical history is negative for any neurological and cardiovascular problems. Physical examination reveals a prominent A wave on the jugular venous pulse and a double apical impulse. There are no audible murmurs. An S4 is present. What is the most likely diagnosis? Options: A) Hypertrophic cardiomyopathy B) Aortic stenosis C) Takotsubo cardiomyopathy D) Restrictive cardiomyopathy Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.