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': 'True about SAF \nSelect and explain. \nA. Are self adjusting files, B. Confirms to 3D root canal anatomy, C. Classified in group 4 of ISO classification, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]