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
What is minimum of amount of taper that should be maintained for an ideal tooth preparation? 
Select and explain. 
A. 4 degree, B. 5 degree, C. 6 degree, D. 12 degree
C: 6 degree
Answer: C: 6 degree 
Explanation: None