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': 'The first gastrectomy was performed in 1881 by ? \nSelect and explain. \nA. Mickuliz, B. Wolfer, C. Billroth, D. Moynihan', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Billroth", 'role': 'assistant'}]