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': 'Most characteristic finding of retinitis pigmentosa –a) Ring scotomab) Peripheral field defectc) Central scotomad) Diplopia \nSelect and explain. \nA. ac, B. a, C. ad, D. ab', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ring scotoma is a peripheral field defect, which is characteristic finding of retinitis pigmentosa.\n\n"Peripheral vision loss is hallmark of retinitis pigmentosa, with the classic ring scotoma 30 -50 degree from fixation" __\xa0Pediatric retina by Hartnett.\n"The ring scotoma is the characteristic field defect of retinitis pigmentosa". —Harley\'s pediatric ophthalmology', 'role': 'assistant'}]