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': 'Regular inspection of hand files may aid in avoidance of instrument separation. What file defects should be looked for on inspection? \nSelect and explain. \nA. Unwinding of the flutes, B. Rolling up or tightening of the flutes, C. Distortion of the tip, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]