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
Which of the following orthodontic wire has least modulus of elasticity? 
Select and explain. 
A. NiTi, B. Beta titanium, C. Stainless steel, D. Co-Cr-Ni
A: NiTi
Answer: A: NiTi 
Explanation: None