In the human knee-jerk reflex, as the calf is raised from the vertical toward the horizontal, the muscles of the quadriceps (flexors on the ventral side of the thighs) and the muscles of the hamstring (extensors on the dorsal side of the thighs) are
A) both excited and contracting.
B) both inhibited and relaxed.
C) excited and inhibited, respectively.
D) inhibited and excited, respectively.
