Which of the following groups of farm equipment use electricity as their source ...

This question is asking which group of farm equipment uses electricity as their source of power.

The correct answer is Option A: milking machine, incubator, and refrigerator.

Milking machines, incubators, and refrigerators are all examples of farm equipment that require electricity to function.

Milking machines are used to automatically milk cows, and they rely on electricity to power the vacuum pump that creates suction to extract milk from the udder.

Incubators are used to hatch eggs, and they use electricity to maintain the proper temperature and humidity levels necessary for the eggs to develop and hatch into chicks.

Refrigerators are used to store perishable items such as harvested crops or dairy products, and they require electricity to keep the interior cool and prevent spoilage.

Option B, Option C, Option D, and Option E do not include all the farm equipment that use electricity as their power source, so they are incorrect answers.

To summarize, milking machines, incubators, and refrigerators are examples of farm equipment that use electricity as their source of power.