This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hea Sounds, Subject name: Medicine
[{'content': 'Severity of mitral stenosis is best identified by? \nSelect and explain. \nA. Loud S1, B. Loud opening snap, C. Duration of mid-diastolic murmur, D. Intensity of mid-diastolic murmur', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Severity of mitral Stenosis Implies that the mitral valve orifice has become smaller in size. So, blood will take longer to go from left atrium to left ventricle. Therefore, length of murmur will increase.', 'role': 'assistant'}]