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: Radiology
[{'content': 'Transverse myelitis usually presents \nSelect and explain. \nA. 1 – 2 weeks, B. 1 – 2 months, C. 4 – 6 months, D. 1 year', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Usual time of onset of symptoms of post-radiation transverse myelitis is 12-24 months but can occur as early as 6 months after radiation.', 'role': 'assistant'}]