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
Application of 2-3 layers of varnish covers: 
Select and explain. 
A. 55% of surface area, B. 60-80% of surface area, C. 90% of surface area, D. 70% of surface area
B: 60-80% of surface area
Answer: B: 60-80% of surface area 
Explanation: Single layer of varnish covers 55% of surface area.