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: Ophthalmology
Wavelength of ND: Yag laser: 
Select and explain. 
A. 1040 nm, B. 1040 mm, C. 1040 cm, D. 1040 m
A: 1040 nm
Answer: A: 1040 nm 
Explanation: Ans. 1040 nm