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
An elderly male with heart disease presents with sudden loss of vision in one eye; examination reveals cherry red spot; diagnosis is – 
Select and explain. 
A. Central retinal vein occlusion, B. Central retinal artery occlusion, C. Amaurosis fugax, D. Acute ischemic optic neuritis
B: Central retinal artery occlusion
Answer: B: Central retinal artery occlusion 
Explanation: Amongst the given options only CRAO causes sudden painless loss of vision along with cherry red spot.