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: Pediatrics
[{'content': 'The commonest valvular manifestation of acute as well as previous rheumatic carditis is \nSelect and explain. \nA. Mitral stenosis, B. Mitral regurgitation, C. Aoic stenosis, D. Aoic regurgitation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Mitral regurgitation (MR) is the commonest manifestation of acute as well as previous rheumatic carditis. Reference: Essential Paediatrics; O.P. Ghai; Page no: 438', 'role': 'assistant'}]