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
Point used as termination of Root canal procedure is 
Select and explain. 
A. Apical constriction, B. Apical foramen, C. Both, D. None
A: Apical constriction
Answer: A: Apical constriction 
Explanation: None