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 child presents with sudden loss of vision with painful ocular movements. The eye is white and there are no obvious signs on ophthalmoscopy. The most likely diagnosis is \nSelect and explain. \nA. Optic nerve glioma, B. Retrobulbar neuritis, C. Craniopharyngioma, D. Eales disease', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Retrobulbar neuritis', 'role': 'assistant'}]