This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Medicine
Most common plasma cell tumor is - 
Select and explain. 
A. Plasmacytoma, B. Waldenstorm's macroglobinemia, C. Multiple myeloma, D. Primary amyloidosis
C: Multiple myeloma
Answer: C: Multiple myeloma 
Explanation: Multiple myeloma is a malignant proliferation of plasma cells. In multiple myeloma,plasma cells produce immunoglobulin of a single heavy & light chain,a monoclonal protein commonly referred to as paraprotein.In some cases,only light chain is produced & this appears in the urine as Bence Jones protein .Reference:Davidson's principles & practice of medicine 22nd edition pg no 1046.