A tennis player serving a ball is employing the ________ system.

The pyramidal system, also known as the intentional system, is responsible for voluntary motor control. It originates in the cerebral cortex and travels down to the spinal cord, facilitating the precise and intentional movements needed for activities like serving a tennis ball. This system allows the player to consciously control their arm, wrist, and hand movements to accurately strike the ball.

In this context, serving in tennis requires a high level of coordination and intention—attributes directly linked to the pyramidal system. The ability to aim and control the force of the serve demonstrates the involvement of this system in executing voluntary motor tasks.

Other systems mentioned, such as the extrapyramidal system, primarily support involuntary and reflexive movements. The autonomic system regulates involuntary bodily functions such as heart rate and digestion, and the central system does not refer specifically to voluntary motor control. Therefore, the pyramidal system is the most appropriate choice, as it directly relates to the voluntary control exercised during a tennis serve.