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
All are exploring instruments for a root canal except: 
Select and explain. 
A. DG-16, B. JK-17, C. CK-17, D. JW-17
B: JK-17
Answer: B: JK-17 
Explanation: The DG-16 endodontic explorer is used to identify canal orifices and to determine canal angulation.
The CK-17 endodontic explorer serves the same purpose, but it's thinner, stiffer tip can be useful for identifying calcified canals.
Micro JW-17 - Thin Canal Explorer, Double-Ended, Single instrument.

JK-17  - Dental explorer or sickle probe.