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
Length of blade in a no 10 and no 40 k file is respectively 
Select and explain. 
A. 16 and 25, B. 25 and 16, C. 16 for both, D. 25 and 22
C: 16 for both
Answer: C: 16 for both 
Explanation: None