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
According to ISO classification powered instruments with high speed rotary can be classified as 
Select and explain. 
A. Group 1, B. Group 2, C. Group 3, D. Group 4
C: Group 3
Answer: C: Group 3 
Explanation: None