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
Commonest malignant bone tumor is 
Select and explain. 
A. Multiple myeloma, B. Osteosarcoma, C. Ewings sarcoma, D. Giant cell tumor
A: Multiple myeloma
Answer: A: Multiple myeloma 
Explanation: Refer Robbins page no 8th 609-611 Multiple also called as Kahlers disease