Root value of ankle jerk-

Answer is D S1The ankle jerk reflex, also known as the Achilles reflex, occurs when the Achilles tendon is tapped while the foot is dorsiflexed.It is a type of stretch reflex that tests the function of the gastrocnemius muscle and the nerve that supplies it.A positive result would be the jerking of the foot towards its plantar surface.Being a deep tendon reflex, it is monosynaptic. It is also a stretch reflex.These are monosynaptic spinal segmental reflexes.When they are intact, integrity of the following is confirmed: cutaneous innervation, motor supply, and coical input to the corresponding spinal segment.This reflex is mediated by the S1 spinal segment of the spinal cord.