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
Re-etching saliva contaminated etched enamel should be done for 
Select and explain. 
A. 30 seconds, B. 20 seconds, C. 10 seconds, D. 5 seconds
C: 10 seconds
Answer: C: 10 seconds 
Explanation: None