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': 'The purpose of a root canal sealer is to: \nSelect and explain. \nA. Seal the tubules of the dentine, B. Stimulate healing in periapical region, C. Prevent discoloration, D. Fill the space between solid core material and the pulp canal walls', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]