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 seen in papilloedema EXCEPT \nSelect and explain. \nA. Hyperemia of disc, B. Sudden vision loss, C. Both, D. None', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Sudden loss of vision', 'role': 'assistant'}]