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': '"Problem village" include all EXCEPT: \nSelect and explain. \nA. Where no water source in a distance of 1.6 km from community, B. Water is available at a depth of more than 15 metres, C. There is excess of Na+, iron & fluoride salt, D. Risk of Guinea worm infection', 'role': 'user'}, {'content': 'Answer: D \nExplanation: - 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 metres, 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'}]