What is the commercial unit of electric energy?

Kilowatt hour

The correct answer is option 3. Kilowatt hour.

The commercial unit of electric energy is Kilowatt hour.

The kilowatt hour (kWh) is a measure of energy equivalent to one kilowatt (1 kW) of power consumed for one hour (1 h). It is commonly used as a billing unit by electric utilities to measure the amount of electricity consumed by households and businesses. The kilowatt hour is a practical unit for measuring and billing electric energy usage because it reflects both the power (in kilowatts) and the duration of usage (in hours).