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
Thickness of luting cement is: 
Select and explain. 
A. 20-40 μ, B. 10-20 μ, C. 60-80 μ, D. 1-2 μ
A: 20-40 μ
Answer: A: 20-40 μ 
Explanation: None