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
Reamers and files differ mainly in: 
Select and explain. 
A. Cross sectional form, B. Colour coding, C. Number of flutes along the blade, D. Instrument formula
C: Number of flutes along the blade
Answer: C: Number of flutes along the blade 
Explanation: None