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
Delayed hypersensitivity reaction is mediated by ? 
Select and explain. 
A. B lymphocyte, B. NK cell, C. Mast cell, D. T lymphocyte
D: T lymphocyte
Answer: D: T lymphocyte 
Explanation: Ans. is 'd' i.e., T lymphocytes