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 ideal dimension for the luting agent space is 
Select and explain. 
A. 0-20 microns, B. 20-40 microns, C. 40-80 microns, D. 80-120 microns
B: 20-40 microns
Answer: B: 20-40 microns 
Explanation: None