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: Orthopaedics
[{'content': 'True about bone tumor is - \nSelect and explain. \nA. Multiple myeloma-more than 55 years age and above, B. Osteogenic sarcoma-fourth decade, C. Chondrosarcoma-first decade, D. Osteoclastoma-fifth decade', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]