This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Guillian Barre syndrome & Alzheimer's disease, 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 & ankle jerks, C. Sacral anesthesia, D. Lower sacral & coccygeal involvement', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The root value of Conus medullaris is S1-S5. Hence in conus medullaris syndrome, knee-jerk is preserved but ankle jerk is lost. Due to the involvement of coicospinal pathway, extensor plantars will be seen.', 'role': 'assistant'}]