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
Clinical features of Conus Medullaris syndrome include all of the following Except: 
Select and explain. 
A. Plantar Extensor, B. Absent knee & ankle jerks, C. Sacral anesthesia, D. Lower sacral & coccygeal involvement
B: Absent knee & ankle jerks
Answer: B: Absent knee & ankle jerks 
Explanation: 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.