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
[{'content': 'Vitreous hemorrhage is caused commonly by: March 2013 (f) \nSelect and explain. \nA. Retinal aery occlusion, B. Retinal vein occlusion, C. Retinitis pigmentosa, D. Retinoblastoma', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B i.e. Retinal vein occlusion', 'role': 'assistant'}]