Final answer:
Voluntary muscle movement originates in an area of the cortex called the primary motor cortex, which is located on the frontal lobe. The correct option is c.
Step-by-step explanation:
This region of the cerebral cortex is specifically located in the precentral gyrus. Neurosurgeon Walter Penfield contributed significantly to our understanding of the primary motor cortex by electrically stimulating the surface of the cerebrum, particularly the precentral gyrus, while patients were under local anesthesia.
This stimulation led to muscle movement, which illustrated the direct stimulation capabilities of this area. The primary motor cortex not only plans movements but also sends the principle output to stimulate spinal cord neurons, which in turn initiate skeletal muscle contraction.
The primary motor cortex receives input from several brain areas that assist in movement planning, while the cells from this cortex are the upper motor neurons that control cells in the spinal cord. Involvement of the upper motor neuron (UMN) and the lower motor neuron (LMN) is necessary for voluntary movements to occur.
Meanwhile, the frontal lobe is also home to secondary motor cortices, such as the premotor cortex and the supplemental motor area, which are involved in generating motor responses based on the actions originated in the prefrontal cortex and planning phases of movements. Hence, c is the correct option.