You are answering a USMLE-style medical question. Question: A 28-year-old female visits her physician for workup of a new onset diastolic murmur found on physical examination. Past medical history is insignificant. Her temperature is 37.0 degrees C, blood pressure is 115/75 mm Hg, pulse is 76/min, and respiratory rate is 16/min. The patient denies dyspnea, fatigue, and syncope. Transthoracic echocardiography reveals a large, pedunculated tumor in the left atrium. This patient is most at risk for: Options: A) Abrupt hypotension B) Sudden cardiac death C) Acute arterial occlusion D) Septic embolism Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.