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 endodontic treatment, the apical foramen is closed due to deposition of: 
Select and explain. 
A. Bone, B. Cementum., C. GP., D. Sealer.
B: Cementum.
Answer: B: Cementum. 
Explanation: Cementum is an ideal apical seal after obturation.