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
The free gingival graft is placed on: 
Select and explain. 
A. On the periosteum, B. Bone, C. Gingiva, D. Periodontal pocket
A: On the periosteum
Answer: A: On the periosteum 
Explanation: None