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
All of the following are causes of sudden painless loss of vision except: 
Select and explain. 
A. Central retinal aery occlusion, B. Optic atrophy, C. Optic neuritis, D. Retinal detachment
B: Optic atrophy
Answer: B: Optic atrophy 
Explanation: Ans. Optic atrophy