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: Microbiology
[{'content': 'Delayed hypersensitivity reaction is mediated by ? \nSelect and explain. \nA. B lymphocyte, B. NK cell, C. Mast cell, D. T lymphocyte', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., T lymphocytes", 'role': 'assistant'}]