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': 'A daily water supply considered adequate to meet the need for all urban domestic purposes is \nSelect and explain. \nA. 10 litres per capita, B. 20 litres per capita, C. 40-60 litres per capita, D. 150-200 litres per capita', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]