The frontal lobes also include the primary which controls voluntary motor functions.

The correct answer will be- primary motor cortex

Explanation:

The motor cortex is the portion of the brain present in the precentral gyrus of the frontal lobe of the brain.  The motor cortex is thought to be involved in the planning actions and control voluntary actions.

The motor cortex is divided into three regions: premotor cortex, primary motor cortex  and supplementary motor area.

The primary motor cortex is the region of the motor cortex which controls the voluntary movements in the human body by generating the impulse.

Thus, the primary motor cortex is the correct answer.

c is the correct answer!