Which sentence from the article shows the MAIN
problem with fossil fuels?

A- There is no way to know how much coal, oil
and natural gas lie buried within the Earth.

B- These were accumulations of oil and gas that
couldn't be obtained through traditional drilling
techniques

C- The burning of fossil fuels creates carbon
dioxide and other greenhouse gases.

D- Plastics and many other products include
fossil fuels in their recipes.