This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc. (W.B.C), Subject name: Pathology
Multiple myeloma is a tumor of? 
Select and explain. 
A. B-lymphocyte, B. T-lymphocyte, C. Lymph nodes, D. Plasma cell
D: Plasma cell
Answer: D: Plasma cell 
Explanation: Ans. (d) Plasma cell(Ref: Robbins 9th/pg 598-602)Multiple myeloma is a malignant proliferation of plasma cells derived from a single clone.