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 of the following are true for medullated nerve fibres of the retina except: \nSelect and explain. \nA. Appear as a whitish patch usually present around the disc, B. Are commonly seen at bih in premature children, C. Disappear in patients with optic atrophy, D. May cause enlargement of blind spot', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. Are commonly seen at bih in premature children', 'role': 'assistant'}]