Correct Answer: Readily available

Solution : The correct answer is (C) Readily available

The main advantage of commercial energy sources is their ready availability. Commercial energy sources, such as fossil fuels (coal, oil, natural gas), nuclear power, and electricity, are widely accessible and can be easily obtained for various purposes. They have well-established production, distribution, and supply systems, making them readily available for industries, businesses, and households. This availability of commercial energy sources ensures a consistent and reliable energy supply to meet the demands of different sectors.