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: Medicine
[{'content': 'Clinical features of Conus Medullaris syndrome include all of the following, except: \nSelect and explain. \nA. Plantar extensor, B. Absent knee and ankle jerks, C. Sacral anesthesia, D. Lower sacral and coccygeal involvement', 'role': 'user'}, {'content': "Answer: B \nExplanation: In conus medullaris syndrome knee jerks are preserved while the ankle jerks are affected. It is an impoant feature differentiating it with cauda equina syndrome. Ref: Harrison's Principles of Internal Medicine, 16th Edition, Pages 2439-40; Neurology Oral Boards Review: A Concise and Systematic Approach to Clinical Practice By Eroboghene E. Ubogu, Page 46", 'role': 'assistant'}]