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': 'Method of Gutta purcha removal from canal for post preparation: \nSelect and explain. \nA. Chemical GP solvent, B. Thermal, C. Mechanical, D. All of the above.', 'role': 'user'}, {'content': 'Answer: D \nExplanation: chemical method is not recommended as no control on length of removal.\nWhile thermal (heated plugger), mechanical ( peaso reamer) have equal efficiency.', 'role': 'assistant'}]