This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Water, Subject name: Social & Preventive Medicine
[{'content': 'Minimum recommended level of Residual chlorine in Swimming pools is: \nSelect and explain. \nA. 0.5 mg/L, B. 0.7 mg/L, C. 1.0 mg/L, D. 2.0 mg/L', 'role': 'user'}, {'content': 'Answer: C \nExplanation: - Level of residual chlorine to be maintained for swimming pool sanitation is > 1.0 mg/L with contact period of 1 hour. - Also Remember, Free/ residual chlorine levels recommended in:- Drinking water = >= 0.5 mg/ L ; with contact period of 1 hour. Drinking water to kill cyclops = >= 2.0 mg/L ; with contact period of 1 hour.', 'role': 'assistant'}]