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: Physiology
[{'content': 'Helper and cytotoxic cells belong to: \nSelect and explain. \nA. T cells, B. B cells, C. Monocytes, D. Macrophages', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. T cells', 'role': 'assistant'}]