Final answer:
To change coordinates to jog in JOINT mode, the correct button to press is the Joint button, which enables independent movement of each robot joint.
Step-by-step explanation:
To change coordinates to jog in JOINT mode, you need to press the Joint button. In robotic systems, JOINT mode allows the operator to move each robot joint independently.
The Jog button typically moves the robot in the currently selected coordinate system, while the Coordinate button would likely switch between different coordinate systems, and the Mode button might switch between different operating modes.
However, it's the Joint button that is specifically designed to adjust the joints of the robot.