Final answer:
The actuators in a dairy farm gate system are likely to be pneumatic arms that move the gates to direct cows into different areas. These actuators act upon receiving signals to control the movement of the gates. The correct answer is B.
Step-by-step explanation:
When the gate system at a dairy farm is described as closing one gate and opening another to direct a cow into a particular area, the actuators involved in this process are likely to be pneumatic arms on the gate mechanism. Actuators are the components in a mechanical system that are responsible for the movement or control of a mechanism or system. In this context, pneumatic arms are typically used because they can provide the necessary force to move the heavy gates in a controlled and efficient manner.
These arms receive signals from the control system to actuate the gates. The other options given, such as RF antennae, light sensors, and movement sensors might be involved in the detection and identification of the cows but they do not perform the physical act of moving the gates, which is the responsibility of the actuators.