This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Multiple Myeloma, Subject name: Orthopaedics
Most common primary malignancy of bone is? 
Select and explain. 
A. Multiple myeloma, B. Osteoid osteoma, C. Osteosarcoma, D. PNET
A: Multiple myeloma
Answer: A: Multiple myeloma 
Explanation: Ans. (a) Multiple myelomaRef.'.Apley's 8/e, p 191)