The correct option is D All of these.
Burning of fossil fuel creates smoke and carbon dioxide. Fossil fuels are the major energy source, as of the current scenario, for generating electricity, industrial usage, fuel in vehicles etc. Therefore, smoke produced from the burning of fossil fuels is a major source of pollution and the carbon dioxide produced by burning the fossil fuels causes greenhouse effect which in turn contributes to global warming. Fossil fuels are found deep under the earth so there have been many accidents in mines which have cost many human lives.