Which of the following is an example of natural gas?

Methane is a simple hydrocarbon and is the primary component of natural gas. It forms through the decomposition of organic materials in environments devoid of oxygen, such as swamps or the deep sea. This process, along with the geological pressure and heat over time, converts these materials into natural gas, making methane the most common and significant constituent. Natural gas, primarily used as a fuel source for heating, cooking, and electricity generation, is valued for being cleaner-burning compared to other fossil fuels.

The other options, while related to fossil fuels or hydrocarbons, do not specifically represent natural gas. Coal is a solid fossil fuel, petroleum is a liquid fossil fuel, and suntan oil is a synthetic product used for skin protection, not a natural gas source. Therefore, methane stands out as the correct answer due to its direct classification as natural gas.