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
The functional cusps are bevelled in the preparation of posterior cast crowns: 
Select and explain. 
A. To reduce the stress at the line angles, B. To prevent the fracture of the tooth structure, C. For the structural durability of the restoration, D. To help in the retention
C: For the structural durability of the restoration
Answer: C: For the structural durability of the restoration 
Explanation: None