question: Q:A 28-year-old man presents to the clinic with increasing shortness of breath, mild chest pain at rest, and fatigue. He normally lives a healthy lifestyle with moderate exercise and an active social life, but recently he has been too tired to do much. He reports that he is generally healthy and on no medications but did have a ‘cold’ 2 weeks ago. He does not smoke, besides occasional marijuana with friends, and only drinks socially. His father has hypertension, hyperlipidemia, and lung cancer after a lifetime of smoking, and his mother is healthy. He also has one older brother with mild hypertension. His pulse is 104/min, the respiratory rate 23/min, the blood pressure 105/78 mm Hg, and the temperature 37.1°C (98.8°F). On physical examination, he is ill-appearing and has difficulty completing sentences. On auscultation he has a third heart sound, and his point of maximal impact is displaced laterally. He has 2+ pitting edema of the lower extremities up to the knees. An ECG is obtained and shows premature ventricular complexes and mildly widened QRS complexes. An echocardiogram is also performed and shows global hypokinesis with a left ventricle ejection fraction of 39%. Of the following, what is the most likely cause of his symptoms?? 
  {'A': 'Acute myocardial infarction', 'B': 'Unstable angina', 'C': 'Coxsackievirus infection', 'D': 'Amyloidosis', 'E': 'Cocaine abuse'},