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': "A young patient present with significant loss of central vision and a normal ERG. There is no obvious family history of similar presentation. The most likely diagnosis: \nSelect and explain. \nA. Best's disease, B. Stargardt's disease, C. Retinitis pigmentosa, D. Cone-rod dystrophy", 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. Stargardt's disease", 'role': 'assistant'}]