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': 'Maxillary first molar has how many roots? \nSelect and explain. \nA. 1 facial and 2 lingual, B. 1 lingual and 2 facial, C. 1 mesial and 2 buccal, D. 1 mesial and 1 distal', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]