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 Fishman’s index, how many sites are there? \nSelect and explain. \nA. 4, B. 6, C. 7, D. 8', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]