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
After glucose rinse, the duration for which  pH drop is seen in interproximal plaque: 
Select and explain. 
A. 20 minutes, B. 60 minutes, C. 120 minutes, D. 180 minutes
C: 120 minutes
Answer: C: 120 minutes 
Explanation: None