This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
[{'content': 'Pulsus alternans occurs in - \nSelect and explain. \nA. Constrictive pericarditis, B. Viral myocarditis, C. Hypokalemia, D. Myocardial infarction', 'role': 'user'}, {'content': 'Answer: D \nExplanation: pulses alternans is seen in 3 conditons a)large pericardial effusion b)left ventricular failure c)asthma so the answer is MI where there is left ventricular failure. Ref Harrison 20th edition pg 1523', 'role': 'assistant'}]