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': "A robust male baby with vigorous feeding and immediate vomiting at 2 months of age. Most probable diagnosis is: \nSelect and explain. \nA. Paralytic ileus, B. Hirschsprung's disease, C. Brain tumor, D. Congenital hyperophic pyloric stenosis", 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans is 'd' i.e. Congenital hyperophic pyloric stenosis", 'role': 'assistant'}]