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
Substantivity of chlorhexidine remains upto 
Select and explain. 
A. 4 hours, B. 8 hours, C. 12 hours, D. 16 hours
C: 12 hours
Answer: C: 12 hours 
Explanation: None