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': 'ISO has classified instrument on the basis of \nSelect and explain. \nA. Method of use, B. Use of instrument, C. Newer instruments, D. Cutting efficiency', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]