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
The cutting efficiency of a bur is improved by 
Select and explain. 
A. Applying more pressure, B. More number of blades, C. Large size of bur, D. Rake angle
D: Rake angle
Answer: D: Rake angle 
Explanation: None