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: Unknown
[{'content': "Most common heart disease in pregnancy is- \nSelect and explain. \nA. ASD, B. Eisenmenger's, C. MS, D. AS", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans: C', 'role': 'assistant'}]