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': 'Root canal sealer ADA specification : \nSelect and explain. \nA. 12, B. 20, C. 47, D. 57', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]