Which of the following is a component of the manipulator?

The link arm is a fundamental component of a manipulator, serving as the connection between the base and the end effector (the part of the manipulator that interacts with the environment, such as a gripper or tool). The link arm's primary function is to provide the necessary reach and articulation that allows the manipulator to perform tasks with precision and range. Its design and movement capabilities enable the manipulator to achieve various positions and orientations, making it essential for diverse applications in automation, robotics, and manufacturing.

In contrast, while electric motors are crucial for driving movements, they are generally considered components that power the manipulator rather than parts of its physical structure. Conveyor belts and safety switches, while important in automated systems, do not serve as intrinsic structural elements of a manipulator itself. Thus, the link arm stands out as the correct answer due to its integral role in the manipulator's design and function.