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
Electronic apex locator is used in Endodontics to determine the 
Select and explain. 
A. Root canal morphology, B. Working length, C. Pulp stone Location, D. Pulp vitality
B: Working length
Answer: B: Working length 
Explanation: None