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': 'The criteria for carrying out a mitral valvuloplasty includes all of the following except- \nSelect and explain. \nA. significant symptoms, B. Isolated mitral stenosis, C. Mobile noncalcified valve, D. Left atrial thrombus', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]