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
True about Rotary NiTi files is 
Select and explain. 
A. Made by Equiatomic alloy of Ni and Ti, B. Developed by WF Buehlar at Navel ordinance laboratory, C. 45% by weight of Titanium and 55% by wt of Nickle, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: None