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': 'The average root surface area (mm2) of the maxillary 2nd\npremolar is \nSelect and explain. \nA. 234, B. 220, C. 273, D. 204', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]