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
All of the following are features of Monoclonal Gammopathy of Undetermined Significance (MGUS), EXCEPT: 
Select and explain. 
A. M protein in serum, B. Bone marrow clonal plasma cells >10%, C. No evidence of other B cell proliferative disorders, D. No myeloma-related organ or tissue impairment
B: Bone marrow clonal plasma cells >10%
Answer: B: Bone marrow clonal plasma cells >10% 
Explanation: Bone marrow plasma cells are less than 10 % in MGUS. Ref:Harrisons Principles of Internal Medicine, 18th Edition, Page 940