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
How much luting agent is required for cementation of crown? 
Select and explain. 
A. 3/4th filled slightly upto the margin, B. 1/4th filled, C. 1/2 filled, D. Full to prevent bubble
C: 1/2 filled
Answer: C: 1/2 filled 
Explanation: None