Answer: d. all of the above
Fossil fuels such as coal, oil and gas are beneficial sources of energy used by the human society. Fossil fuels are non- renewable resources, which are produced after millions of years of geological and biological activity taking place inside the earth crust. Human society is mainly dependent upon the fossil fuels to maintain it's energy needs.
There are some negative consequences associated with fossil fuels:
Environmental consequences: Fossil fuels are used for generation of energy in the power plants and by the automobiles. These sources releases partially and completely combusted products which includes the poisonous gases causing air and water pollution.
Economic consequences: Fossil fuel use is related with economic crisis because fossil fuels are non- renewable resources, which cannot be replenished once used. They are expensive and many commercial energy generation processes are dependent on them such as electricity, transportation and others.
Development hindrances: Large dependence on fossil fuels creating an hindrance on development process. As, there are very few findings which are resulted which could replace the fossil fuels, these finding can be beneficial for the environmental and economic point of view.