You are answering a USMLE-style medical question. Question: A 60-year-old man comes to the physician for a routine physical examination. He lives in a group home and takes no medications. During the appointment, he frequently repeats the same information and needs to be reminded why he is at the doctor's office. He says that he is a famous poet and recently had a poem published in a national magazine. His vital signs are within normal limits. He has a constricted affect. Neurological examination shows no focal deficits. On mental status examination, he has no long-term memory deficits and is able to count in serial sevens without error. An MRI of the brain shows atrophy of the anterior thalami and small mamillary bodies. Which of the following is the most likely predisposing factor for this patient's condition? Options: A) Consumption of undercooked meat B) Chronic hypertension C) Alcohol use disorder D) Spirochete infection Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.