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
All ceramic crown is placed on mandibular canine, what can we do to prolong the life of crown: 
Select and explain. 
A. Glazing, B. Polishing., C. Out of occlusion (Infraocclusion)., D. Group function.
D: Group function.
Answer: D: Group function. 
Explanation: None