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': 'Which one of the following is the level of residual free chlorine recommended for swimming pool water disinfection ? \nSelect and explain. \nA. 0.5 mgilitre, B. 0.8 mg/litre, C. 1 mg/litre, D. 5 mg/litre', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., I mg/lit", 'role': 'assistant'}]