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 smear layer produce by cavity cutting is approximately about: 
Select and explain. 
A. 0.5 micron thick., B. 1 micron thick., C. 2 micron thick., D. 2.5 micron thick.
B: 1 micron thick.
Answer: B: 1 micron thick. 
Explanation: None