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': "According to Black's classification, caries on lingual pits of maxillary central incisors are: \nSelect and explain. \nA. Class I, B. Class II, C. Class III, D. Class IV", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]