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
Citric acid is applied to root surface: 
Select and explain. 
A. To reduce caries, B. To reduce sensitivity, C. To facilitate collagen fibre adhesion on to root surface, D. None of the above
C: To facilitate collagen fibre adhesion on to root surface
Answer: C: To facilitate collagen fibre adhesion on to root surface 
Explanation: None