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
Infra-bony pockets are treated by: 
Select and explain. 
A. Gingivectomy, B. Gingivoplasty, C. Flap operation, D. Vestibuloplasty
C: Flap operation
Answer: C: Flap operation 
Explanation: None