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': "Opaque white areas covering more than 25% but less than 50% of the tooth surface is given the Dean's score of: \nSelect and explain. \nA. 1, B. 2, C. 3, D. 4", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]