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: Unknown
[{'content': 'Usual presentation of cauda equina syndrome is \nSelect and explain. \nA. Sudden and unilateral, B. Gradual and bilateral, C. Sudden and bilateral, D. Gradual and unilateral', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Conus medullaris syndrome is usually sudden and bilateral whereas cauda equina is grdual and unilateral.', 'role': 'assistant'}]