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
Recommended working speed for light speed instrument is: 
Select and explain. 
A. 550-650 rpm, B. 1000-2000 rpm, C. 5000-10000 rpm, D. 150-250 rpm
B: 1000-2000 rpm
Answer: B: 1000-2000 rpm 
Explanation: None