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': 'Disinfection of water is not required if the source is from- \nSelect and explain. \nA. Tube well, B. Step well, C. Draw well, D. River', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Tube well", 'role': 'assistant'}]