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 lymphoma are positive for all of the following except \nSelect and explain. \nA. CD 20, B. CD 23, C. CD 5, D. CD 43', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Solution\nMantle cell\xa0lymphoma are usually CD23 negative.\nThey are positive for CD5, CD 20, and CD43.', 'role': 'assistant'}]