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': 'Osteosarcoma commonly affects: September 2005 \nSelect and explain. \nA. Metaphysis, B. Diaphysis, C. Epiphysis, D. None of the above', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. A: Metaphysis Metaphysis-common site for osteosarcoma Diachysis- common site for ewing's tumor Epiphysis- common site for osteoclastoma", 'role': 'assistant'}]