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
Currently used radiographic method for working length determination is: 
Select and explain. 
A. Grossman technique, B. Ingels technique., C. Bregman technique., D. None of the above.
B: Ingels technique.
Answer: B: Ingels technique. 
Explanation: None