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': 'Highest incidence of Maxillary extra canal is seen in\nwhich tooth \nSelect and explain. \nA. Maxillary 1 PM, B. Maxillary 1st molar, C. Maxillary 2nd molar, D. Mandibular 1st PM', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]