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
Vortex has 
Select and explain. 
A. M wire phase NiTi, B. R phase NiTi, C. Blue wire technology, D. All of the above
A: M wire phase NiTi
Answer: A: M wire phase NiTi 
Explanation: None