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: Pathology
Which of the following is not a minor diagnositic criteria for multiple myeloma? 
Select and explain. 
A. Lytic bone lesions, B. Plasmacytosis greater than 20%, C. Plasmacytoma on biopsy, D. Monoclonal globuline spike on serum electrophoresis of> 2.5 g/dl for IgG, > 1.5 g/dl for IgA
C: Plasmacytoma on biopsy
Answer: C: Plasmacytoma on biopsy 
Explanation: In the NCCN guidelines, active multiple myeloma is no longer diagnosed using the CRAB criteria (hyperCalcemia, Renal failure, Anemia, Bone lesions) for end-organ damage. The current diagnostic criteria are as follows : Bone marrow clonal plasma cells >=10% or bony or extramedullary plasmacytoma (confirmed by biopsy)