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: Medicine
M spike on serum electrophorosis is seen in - 
Select and explain. 
A. Lymphoblastic leukemia, B. Waldenstrom's macroglobulinaemia, C. Alpha-chain disease, D. AIDS
B: Waldenstrom's macroglobulinaemia
Answer: B: Waldenstrom's macroglobulinaemia 
Explanation: None