This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Maternal and child care, Subject name: Social & Preventive Medicine
[{'content': 'Minimum depth for the lining of a sanitary well is \nSelect and explain. \nA. 5 meters, B. 6 meters, C. 7 meters, D. 8 meters', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The lining of a sanitary well should go down at least 6 meters (20 feet) to ensure that water enters from the bottom and not from the sides of the well.The lining should extend upwards for about 60-90cm (2-3 feet) above the ground.Park 23rd edition pg: 709', 'role': 'assistant'}]