This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
[{'content': 'Virus infected cells killed by: \nSelect and explain. \nA. Natural killer cells, B. Plasma cells, C. B cells, D. None', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a'(Ref: Ananthanarayan, 8th/e, p. 131)Virus infected cells are killed by:(i) Innate immunity-by NK cells.(ii) Adaptive immunity-by cytotoxic T cells.", 'role': 'assistant'}]