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
Chamfer finish line in an anterior three quarter crown mainly imparts 
Select and explain. 
A. Structural durability, B. Retention and Resistance, C. Periodontal preservation, D. None of the above
A: Structural durability
Answer: A: Structural durability 
Explanation: None