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: Dental
[{'content': 'In DMF index, according to WHO specification teeth missing due to any other reason other than caries is designated as \nSelect and explain. \nA. D, B. M, C. F, D. None of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]