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
In an endodontic file, D2 will be 
Select and explain. 
A. At the tip of the instrument, B. At 2mm from the tip of the instrument, C. At 3mm from the tip of the instrument, D. At 16mm from the tip of the instrument
D: At 16mm from the tip of the instrument
Answer: D: At 16mm from the tip of the instrument 
Explanation: None