The stretch receptors of the sensory neurons in the human ...

[Millan]

The stretch receptors of the sensory neurons in the human knee-jerk reflex are located in the
A) gastrocnemius muscle, in the calf.
B) cartilage of the knee.
C) quadriceps, the flexor muscles on the ventral side of the thighs.
D) hamstring, the extensor muscles on the dorsal side of the thighs.
E) brain, the sensorimotor relay.

[Celeste]

C