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: Social & Preventive Medicine
[{'content': 'During the process of chlorination of water, the disinfecting action of chlorine is due to the formation of – \nSelect and explain. \nA. Hydrochloric acid only, B. Hypochlorous acid only, C. Hydrochloric acid and hypochlorite ions, D. Hypochlorous acid and hypochlorite ions', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]