Which of the following best describes fuel gas?

Fuel gas is best described as a commercially distributed product that includes various gases, such as natural gas and liquefied petroleum (LP) gas. This definition encompasses the characteristics and uses of fuel gas in practical applications, such as heating, cooking, and energy production. Natural gas, primarily composed of methane, and LP gas, which can include propane and butane, are both widely used as fuel sources due to their efficiency and availability. This option emphasizes the diversity of substances classified as fuel gases, highlighting their role in commerce and everyday use.

The other options do not accurately encapsulate the full scope of what fuel gas entails. While a mixture of water and gasoline may involve some elements used in fuel production, it does not represent fuel gas. Similarly, gas found solely in the atmosphere would not typically qualify as fuel gas since it lacks the specific composition and utility that designated fuels possess. Lastly, stating that fuel gas is derived solely from petroleum ignores the fact that fuel gas can also be derived from various natural sources and processes beyond petroleum. This broader context illustrates why the best option highlights the commercial aspect and variety of fuel gas products.