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 removable space regainer 
Select and explain. 
A. Open coil, B. Gerber, C. Hotz, D. Split saddle
D: Split saddle
Answer: D: Split saddle 
Explanation: Split saddle is a removable space regainer while other three are fixed space regainer.