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: Radiology
Which type of laser is used in waterlase system? 
Select and explain. 
A. Argon laser, B. Diode Laser, C. Nd:YAG laser, D. YSGG Laser
D: YSGG Laser
Answer: D: YSGG Laser 
Explanation: It is an erbium laser (Er,Cr:YSGG) that has the ability to remove both hard and soft tissue safely and effectively. The WaterLase iPlus™ laser from BIOLASE, he says, is exceptionally versatile. “This is an all-tissue laser. Not only can it manipulate soft tissue by removing it for procedures such as biopsies and gingivectomies, it can also safely and effectively ablate tooth and bone structure.