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': 'Which of the following is a pan-T lymphocyte marker - \nSelect and explain. \nA. CD2, B. CD3, C. CD19, D. CD25', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., CD 3 The most clearcut differentiation between T and B cells is by their surface markers, for example, by Demonstration of CD3 of T cells and 1g on B cells.", 'role': 'assistant'}]