This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous system, Subject name: Physiology
Root value of ankle jerk 
Select and explain. 
A. L3 L4, B. L4 L5, C. S1 S2, D. S3 S4
C: S1 S2
Answer: C: S1 S2 
Explanation: The ankle jerk reflex, also known as the Achilles reflex, occurs when the Achilles tendon is tapped while the foot is dorsiflexed. This reflex is mediated by the S1 spinal segment of the spinal cord. Ref: guyton and hall textbook of medical physiology 12 edition page number: 774,775,776