This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and health, Subject name: Social & Preventive Medicine
[{'content': 'Controlled tipping is method of disposal of - \nSelect and explain. \nA. Sullage, B. Sewage, C. Human excreta, D. Refuse', 'role': 'user'}, {'content': "Answer: D \nExplanation: Park's textbook of preventive and social medicine 23rd edition. * Controlled tipping or sanitary landfill is the most satisfactory method of refuse disposal where suitable land is available.,", 'role': 'assistant'}]