This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Optics and refraction, Subject name: Ophthalmology
Which of the following laser is used in LASIK 
Select and explain. 
A. Excimer, B. Nd-Yag, C. Argon, D. Krypton
A: Excimer
Answer: A: Excimer 
Explanation: LASIK : In this technique first a flap of 130-160 micron thickness of anterior corneal tissue is raised with the help of an automated microkeratome. Recently, femtosecond laser is being used for more accurate and smooth flaps. After creating a corneal flap midstromal tissue is ablated directly with an Excimer Laser beam, ultimately flattening the cornea. Reference: A.K.Khurana; 6th edition ; Page no: 53