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': 'Which of the following is generally the longest root canal on the maxillary first molar? \nSelect and explain. \nA. Mesiobuccal, B. Distobuccal, C. Palatal, D. Distolingual', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]