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 tuberculin test response is due to: September 2004 \nSelect and explain. \nA. B lymphocytes, B. T lymphocytes, C. Monocytes, D. Histiocytes', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B i.e. T lymphocytes', 'role': 'assistant'}]