This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vascular Disorders, Subject name: Ophthalmology
[{'content': 'Cattle track appearance in fundoscopy is due to? \nSelect and explain. \nA. CRAO, B. CRVO, C. Retinitis pigmentosa, D. Diabetic retinopathy', 'role': 'user'}, {'content': "Answer: A \nExplanation: ANSWER: (A) CRAOREF: Elsevier Comprehensive Guide, page 628Common fundoscopy findings:ConditionFindingOptic disc colobomaMorning glory appearanceCRAOCattle track appearance CRVOBlood and thunder fundusChloroquine toxicityBull's eye maculopathyQuinine toxicityCherry red spotRetinitis pigmentosaWaxy pallor of optic disc Bone spicule pigmentationCongenital syphilis/ RubellaSalt and pepper fundusSickle cell anemiaRising sun signCMV retinitisMozzarella pizza fundusAIDSCotton wool spots", 'role': 'assistant'}]