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': 'Not a feature of optic neuritis: \nSelect and explain. \nA. Marcus gunn pupil, B. Reduced color vision, C. Central scotoma, D. Large cup of optic nerve head', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Large optic nerve head is seen in glaucoma, not in optic neuritis. Features of Optic Neuritis (ON) Abrupt vision loss with pain. RAPD (Marcus gunn pupil) Papillitis Macular star in neuroretinitis Decreased contrast sensitivity, colour vision, dark adaptation characteristic. Field defect: Swiss cheese visual field/central/ centrocecal scotoma Delayed VER (Visual Evoked Response) MC systemic disorder a/w Optic neuropathy is MS (Multiple sclerosis)', 'role': 'assistant'}]