This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Musculoskeletal system, Subject name: Anatomy
[{'content': 'Commonest malignant bone tumor is \nSelect and explain. \nA. Multiple myeloma, B. Osteosarcoma, C. Ewings sarcoma, D. Giant cell tumor', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Refer Robbins page no 8th 609-611 Multiple also called as Kahlers disease', 'role': 'assistant'}]