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': 'Four canals are seen in: \nSelect and explain. \nA. Upper 1st molar, B. Lower 1st molar, C. Upper 2nd molar, D. Lower 2nd molar', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]