A 70-year-old woman sees her physician because she has had episodes of chest pain during the past week. She is afebrile. Her pulse is 80/min, respirations are 16/min, and blood pressure is 110/70 mm Hg. On auscultation of the chest, heart sounds seem distant, but the lung fields are clear. Neck veins are distended to the angle of the jaw, even while sitting. There is a darkly pigmented, 1.2-cm skin lesion on the right shoulder. A chest radiograph shows cardiomegaly and prominent borders on the left and right sides of the heart. Pericardiocentes is yields bloody fluid. Laboratory findings include a serum troponin I level of 0.3 ng/mL. Which of the following is the most likely cause of these findings? (A) Calcific aortic stenosis (B) Coronary atherosclerosis (C) Metastases (D) Rheumatic heart disease (E) Tuberculosis