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': 'The DMF index is utilized for \nSelect and explain. \nA. All deciduous teeth, B. All permanent teeth except the third molars, C. Cuspids and molars only, D. Six permanent teeth', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]