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 is a new slow type palatal expander? 
Select and explain. 
A. NiTi expander, B. Hyrax expander, C. Quad helix, D. Molar rotator
A: NiTi expander
Answer: A: NiTi expander 
Explanation: None