This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Which is not a minor diagnostic criteria for multiple myeloma? 
Select and explain. 
A. Lytic bone lesions, B. Plasmacytosis greater than 20%, C. Plasmacytoma on biopsy, D. Monoclonal globulin spike on serum melectrophoresis of >2.5 G/DL for IgG,>1.5 G/DL for IGA)
C: Plasmacytoma on biopsy
Answer: C: Plasmacytoma on biopsy 
Explanation: . Plasmacytoma on biopsy