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': 'Most commonly used material post pulpectomy is: \nSelect and explain. \nA. ZOE., B. Gutta-percha., C. META PEX., D. All of the above.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]