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': 'All are true regarding optic neuritis, EXCEPT: \nSelect and explain. \nA. Decreased visual acuity, B. Decreased pupillary reflex, C. Abnormal electroretinogram, D. Abnormal visual evoked response retinogram', 'role': 'user'}, {'content': "Answer: C \nExplanation: Optic neuritis is inflammation and demyelination of optic nerve. Electroretinogram is therefore not abnormal in optic neuritis. Ref: Parson's Diseases of the Eye, Page 114 ; Comprehensive Ophthalmology By A K Khurana, 4th Edition, Pages 294-5, 488-9", 'role': 'assistant'}]