Answer: A. Pollution
Step-by-step explanation:
Fossil fuels are the fuels which are excavated from undersurface and deep regions of the the earth crust. These are produce by millions of years of decomposition activity of soil microbes on organic matter generated after dead and decaying plants and animals. These fossil fuels are used as a source of energy.
The fossil fuels like coal, petroleum and natural gas produces toxic,harmful and polluting gases like carbon dioxide, carbon monoxide, nitrous oxides on combustion and burning. These gases contaminate the air and water hence causes pollution.
Therefore, the main advantage of using fossil fuel is pollution.