This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Valvular Heart Disease, Subject name: Medicine
[{'content': 'Severe mitral stenosis is 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: Ans.(c) Duration of mid-diastolic murmurRef: Harrison 19th ed. /1539* Severity of mitral Stenosis implies that the mitral valve orifice has become smaller in size. This implies that the blood will take longer time to go from left atrium to left ventricle. This implies the LENGTH Of murmur will increase.', 'role': 'assistant'}]