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': 'Austin flint murmur is seen in cases of \nSelect and explain. \nA. Aortic stenosis, B. Aortic regurgitation, C. Hypertrophic obstructive cardiac myopathy, D. Ventricular stenosis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The Austin Flint murmur of chronic severe AR is a low-pitched mid\xa0to late apical diastolic murmur that sometimes can be confused with MS. The Austin Flint murmur typically decreases in intensity after exposure to vasodilators, whereas the murmur of MS may be accompanied by an opening snap and also may increase in intensity after vasodilators because of the associated increase in cardiac output.', 'role': 'assistant'}]