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: Surgery
[{'content': "Duhamel operation is done in - \nSelect and explain. \nA. Congenital pyloric stenosis, B. Hiatus hernia, C. Achlasia cardia, D. Hirschsprung's disease", 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Hirschsprung's disease", 'role': 'assistant'}]