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
Arrange the following preparations in increasing order of their resisting area 
Select and explain. 
A. A < B < C, B. B < A < C, C. C < B < A, D. C < A < B
C: C < B < A
Answer: C: C < B < A 
Explanation: The resisting area decreases as the preparation taper increases.

For a cylinder with no taper, the resisting area would cover half the axial walls (A).
For an deafly-tapered tooth preparation, the resisting area covers somewhat less than half the axial walls (B).
An over-tapered (20 degrees) preparation has only a small resisting area near the occlusal surface (C).