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': 'MC affected valve in RHD: March 2013 \nSelect and explain. \nA. Mitral, B. Tricuspid, C. Aoic, D. Pulmonary', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A i.e. Mitral In rheumatic fever, the mitral valve is involved most frequently followed by the aoic valve', 'role': 'assistant'}]