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': 'Problem village is all except - \nSelect and explain. \nA. Where no water source in a distance of 1.6 km from community, B. Water is more than depth of 15m, C. There is excess of Na2 Salts, D. Risk of Guinea worm infection', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is `d' i.e., Risk of Guinea worm infection", 'role': 'assistant'}]