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
Pivoting movement better resisted by a tooth preparation if: 
Select and explain. 
A. Diameter is smaller, B. Diameter is large, C. Diameter is large and length is small, D. Do not depend on diameter of tooth
A: Diameter is smaller
Answer: A: Diameter is smaller 
Explanation: None