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': 'Best material for obturating a root canal of a tooth is: \nSelect and explain. \nA. Thermoplastic GP, B. Silver cone, C. Resorbable paste, D. GP with sealer', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]