Correct Answer: Natural gas

Solution : The correct answer is Natural Gas .

Conventional sources of energy are non-renewable energy resources that have been used conventionally for a long time. They are generally limited by what is present in nature, and they will quickly run out if improperly employed. Examples include coal, biomass, oil, natural gas, etc. Unconventional energy sources are those that are not commonly used and include renewable energy sources like solar, wind, tidal, and other energy sources.