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
Which of the following is a pure histological landmark for termination of cleaning and shaping of root canal? 
Select and explain. 
A. CDJ, B. CEJ, C. DEJ, D. None
A: CDJ
Answer: A: CDJ 
Explanation: Cementodentinal junction is considered as a pure histological landmark for termination of cleaning/shaping and obturation.