The correct answer is: D. Any of the above
Load shedding is the planned reduction in electrical load, in order to prevent a power outage. It is usually done when the demand for electricity exceeds the supply. Load shedding can be done by switching off certain loads, reducing the voltage or frequency of the electricity supply, or a combination of these methods.
Switching off certain loads is the most common method of load shedding. This can be done manually, by operators, or automatically, by a load shedding controller. When loads are switched off, the demand for electricity is reduced, and the power grid is stabilised.
Reducing the voltage or frequency of the electricity supply is another method of load shedding. This can be done by the power utility, or by the load shedding controller. When the voltage or frequency is reduced, the demand for electricity is also reduced. However, this method can damage equipment, and is not usually used unless it is absolutely necessary.
Load shedding is a last resort measure, and is only used when there is a risk of a power outage. It can cause inconvenience and disruption to businesses and consumers. However, it is necessary to protect the power grid and ensure that everyone has access to electricity.