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 are features of typical B cell CLL , EXCEPT: 
Select and explain. 
A. Increased monoclonal B cells expressing the CD5 antigen, B. The peripheral blood smear show, C. trisomy 12 is found in 25-30%, D. Abnormalities in chromosome 11-
D: Abnormalities in chromosome 11-
Answer: D: Abnormalities in chromosome 11- 
Explanation: Typical B cell CLL Increased number of monoclonal B cells expressing the CD5 antigen. Bone marrow infiltration by the same cells confirms the diagnosis. The peripheral blood smear shows many "smudge" or "basket" cells,( nuclear remnants of cells damaged by the physical shear stress of making the blood smear). In cytogenetic studies trisomy 12 is found in 25-30% of patients. Abnormalities in chromosome 13 are also seen. Ref: Harrison, E-18,P-926