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: Pathology
[{'content': 'Mantle cell lymphomas are positive for all of the following except- \nSelect and explain. \nA. CD23, B. CD20, C. CD5, D. Cyclin D1', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., CD-23", 'role': 'assistant'}]