Which of the following action words describes the components of a control loop?

The correct choice encapsulates the essential functions that characterize the components of a control loop. A control loop typically involves a series of actions that ensure a system operates at its desired performance level.

"Measure" refers to the collection of data regarding the process variable—such as temperature, pressure, or flow—providing the necessary information to assess current conditions. "Transmit" indicates the movement of this measured data to a processing unit or controller, where actions can be determined based on the current readings. The "Compare" step involves evaluating the measured value against a predetermined set point or target value, allowing for the identification of any deviation. Finally, "Control" entails the actions taken to adjust the process, ensuring that the system continues to function within desired limits, effectively correcting any discrepancies identified during the comparison.

By encompassing all these vital actions, the correct answer accurately reflects the systematic approach that defines control loops in instrumentation and automation contexts.