Question

stimulation of a neuron that terminates in the superior region of the left postcentral gyrus would produce
a sensation in the lips.
a sensation in the right leg.
a muscle twitch in the lips.
a muscle twitch in the right leg.
both sensations and muscle twitches in the right leg.

Explanation:

The postcentral gyrus is the primary somatosensory area. Sensory information from the right side of the body projects to the left postcentral gyrus (contralateral representation). The superior region of the postcentral gyrus is associated with sensations from the lower - body parts like the leg. Since it is a sensory gyrus (not a motor gyrus), it would produce a sensation (not a muscle twitch).

Answer:

a sensation in the right leg.