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': 'Perforins are produced by - \nSelect and explain. \nA. Cytotoxic T cells, B. Suppressor T cells, C. Memory helper T cells, D. Plasma cells', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A protein found in the cytoplasmic granules of both T-cytotoxic lymphocytes and natural killer cells Reff: Ananthanarayan & Panikers textbook of microbiology 9th edition pg: 137', 'role': 'assistant'}]