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
NiTi alloy shows superelasticity through: 
Select and explain. 
A. Conversion from Austenite to Martensite phase, B. Conversion from Martensite to Austenite phase, C. M wire phase, D. Austenite + Martensite + R phase
A: Conversion from Austenite to Martensite phase
Answer: A: Conversion from Austenite to Martensite phase 
Explanation: Superelasticity and shape memory of NiTi alloys is because of phase transformation in their crystal structures when cooled from the stronger, high temperature form (Austenite) to the weaker low temperature form (Martensite).