Which of the following represents the energy consumed over time?

The choice of kilowatt-hour is correct because it represents the amount of energy consumed when a device uses one kilowatt of power for one hour. This unit effectively combines power (measured in kilowatts) and time (measured in hours), providing a concise measure of energy usage.

For context, a kilowatt measures the rate at which energy is used, while a kilowatt-hour accounts for the total energy consumed over a specified time period. This distinction is crucial in understanding how energy consumption is calculated on electricity bills, where the kilowatt-hour is commonly used.

The other options do not represent energy consumed over time: kilowatt is a unit of power, kilovolt-ampere refers to apparent power in an electrical system, and brake horsepower is a measure of output power, typically of engines, without incorporating any time aspect into energy consumption.