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
Multiple myeloma is diagnosed by- 
Select and explain. 
A. 24 hours urine protein, B. Kidney biopsy, C. > 10% plasmacytosis, D. Rouleaux formation in blood
C: > 10% plasmacytosis
Answer: C: > 10% plasmacytosis 
Explanation: Multiple myeloma is diagnosed by marrow plasmacytosis of 1.more than 10% and 2.radiological evidence of lytic Bony lesions and 3. demonstration of Serum and urine and component Reference textbook of Pathology 7th edition author Harsha Mohan page number 363