Final answer:
The correct pointing device that allows you to control the pointer by moving the entire device around on a desk is a trackball.
Step-by-step explanation:
The correct answer is A) Trackball. A trackball is a pointing device that controls the pointer by moving the entire device around on a desk. It consists of a ball that can be rolled with the fingers or palm of the hand to move the pointer on the screen. The movement of the trackball is detected by sensors, allowing for precise control over the pointer.