Arrange the following preparations in increasing order of their resisting area
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).
A < B < C
B < A < C
C < B < A
C < A < B