Answer: D) Increased greenhouse gases
The burning of fossil fuels such as coal, natural gas, oil for the production of electricity, thermal energy and running the automobiles releases large amount of green house gases such as carbon dioxide, methane, and nitrous oxide. These gases causes pollution, they have the molecular structure, which traps the sunlight, makes the global atmospheric temperature warm, resulting in greenhouse effect.
Also, the fossil fuels are non- renewable resources which cannot be replenished once used, also the excavation process of these fossil fuels is difficult and cost effective. Hence, these are not available in cheap prices.
On the basis of the above information, the increased greenhouse gases is the environmental cost of fossil fuel consumption as these are polluting the environment.