This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuro-Ophthalmology, Subject name: Ophthalmology
[{'content': 'Diagnose the ocular pathology. \nSelect and explain. \nA. Primary optic atrophy, B. Primary open angle glaucoma, C. Papilledema, D. Central retinal artery occlusion', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. (c) PapilledemaOption a - should be a pale - white disc.Option b - POAG should present with loss of nasal neuro- retinal rim and Cupping (large cup, c/d ratio >0.5) along with vascular changes.Option d - CRAO - no occlusion can be seen, all arteries (thinner cross-section, red colour) and veins (thicker cross section, darker red color) are seen to be patientOption c - Papilledema - earliest sign is blurring of the disc margins, which is visible in the image.', 'role': 'assistant'}]