This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'An early systolic murmur may be caused by all of the following, EXCEPT: \nSelect and explain. \nA. Small ventricular septal defect, B. Papillary muscle dysfunction, C. Tricuspid regurgitation, D. Aoic stenosis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: In Aoic stenosis, murmur is ejection systolic ie: murmur stas after the isovolumic or isometric contraction phase. So the murmur stas only after the opening of the semilunar valve. In all the other conditions murmur stas in the isometric contraction phase itself, so its early systolic.', 'role': 'assistant'}]