The correct answer is D. All of the above.
Vacuum cleaners, fan motors, and pistol drills are all examples of devices that always have some load whenever switched on. This is because they all have moving parts that require power to operate. The load on these devices can vary depending on the specific application, but it is always present.
For example, a vacuum cleaner will have a higher load when it is cleaning a thick carpet than when it is cleaning a hard floor. This is because the carpet provides more resistance to the movement of the vacuum cleaner’s brushroll.
A fan motor will also have a higher load when it is blowing air against a strong wind than when it is blowing air in a still room. This is because the wind provides more resistance to the movement of the fan’s blades.
A pistol drill will have a higher load when it is drilling through a hard material than when it is drilling through a soft material. This is because the hard material provides more resistance to the movement of the drill’s bit.
In all of these cases, the load on the device will cause it to draw more current from the power supply. This increased current can cause the device to heat up, so it is important to make sure that the power supply is able to handle the load.