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': "Extent of severity index, the examination \nSelect and explain. \nA. Involves all teeth, B. Only six teeth, C. Is done with naber's probe, D. None of the above", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]