This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitreous and retina, Subject name: Ophthalmology
[{'content': 'A 40 year old male with diabetes presents with vitreous hemorrhage. What is the cause? \nSelect and explain. \nA. Posterior retinal detachment, B. Neovascularization at disc, C. Central retinal vein occlusion, D. Trauma to central retinal aery', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Neovascularization, defined as abnormal formation of blood vessels in the retina, is a sight-threatening condition indicative of late-stage diabetic retinopathy (DR). ...Neovascularization on the disc (NVD) is diagnosed when new vessels are located within one disc-diameter of the optic disc. Ref AK khurana 6/e p 278', 'role': 'assistant'}]