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
In NiTi rotary electric handpiece, rotation should be 
Select and explain. 
A. 350-450, B. 250-300, C. 150-300, D. 100-150
C: 150-300
Answer: C: 150-300 
Explanation: None