Correct Answer: Kilowatt-hour

Solution : The correct option is Kilowatt hour.

A kilowatt-hour (kWh) is a unit of electrical energy. It is commonly used to measure the amount of energy consumed over time. It's the standard unit for billing and pricing electricity usage in most places around the world. One kWh is the amount of energy required to sustain a power load of one kilowatt for one hour.