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 problem village is one where ? \nSelect and explain. \nA. Source of water > 1.6 km away, B. Water available > 15 meters depth, C. Excess of fluoride in water, D. All of the above', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is `d' i.e., All of the above A problem village has been defined as one Where no source of safe water is available within a distance of 1.6 km, or Where water is available at a depth of more than 15 meters, or Where water source has excess salinity, iron, fluorides and other toxic elements, or Where water is exposed to the risk of cholera.", 'role': 'assistant'}]