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': 'High speed includes the R.P.M between \nSelect and explain. \nA. 20000-50000, B. 50000-100000, C. 100000-200000, D. above 200000', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]