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': 'Tumors arising from all the following structures produce papilloedema except \nSelect and explain. \nA. Cerebrum, B. Cerebellum, C. Thalamus, D. Medulla', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Tumor of\xa0 medulla rarely produce papilloedema.', 'role': 'assistant'}]