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': 'Cystosarcoma phyllodes are treated by \nSelect and explain. \nA. Simple mastectomy, B. Radical mastectomy, C. Modified radical mastectomy, D. Hadfields operation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Phyllodes tumor is usually benign and treated by simple mastectomy.', 'role': 'assistant'}]