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': 'Not a B cell marker - \nSelect and explain. \nA. CD 19, B. CD 20, C. CD 134, D. CD 10', 'role': 'user'}, {'content': 'Answer: C \nExplanation: . CD 134', 'role': 'assistant'}]