Answer: D. natural gas
Step-by-step explanation:
Fossil fuels are the source of energy that are excavated from the deep layers of the earth crust. They are produced after year long microbial activity over the decayed plant and animal matter. Natural gas is the fossil fuel which is a naturally occurring natural gas which primarily consists of methane, but also contains alkanes, carbon dioxide, hydrogen sulfide, and helium.
It is the most common type of fossil fuel used for heating and cooking purposes. As it is cheapest in price as compared to other fuels and emits less amount of gaseous waste after combustion. Therefore, does not create pollution in house when used for heating and cooking.