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: Unknown
[{'content': 'Disinfecting action of chlorine in chlorination of water is mainly due to: \nSelect and explain. \nA. Hypochlorite ion, B. Chloride ion, C. Sodium chloride, D. Hypochlorous acid', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ref. Foundations of Community medicine. Page. 62\n\xa0\nChlorination\n\nThe disinfecting action of chlorine is predominantly due to hypochlorous acid.\nHypochlorous acid is most effective form of chlorine and it is almost 70-80 times more effective', 'role': 'assistant'}]