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
Optimal landmark for termination of cleaning, shaping and obturation is 
Select and explain. 
A. Cementodentinal junction, B. Apical constriction, C. Minor diameter, D. All of the above
A: Cementodentinal junction
Answer: A: Cementodentinal junction 
Explanation: None