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
Snow blindness is caused by : 
Select and explain. 
A. Ultravoilet rays, B. Infrarads, C. Microwaves, D. Defect in mirror
A: Ultravoilet rays
Answer: A: Ultravoilet rays 
Explanation: A i.e. Ultra violet rays