According to the Environmental Protection Agency (EPA), which one of the following is the largest source of sulphur dioxide emissions ?

According to the US Environmental Protection Agency (EPA), the largest source of sulphur dioxide (SO2) emissions in the atmosphere is the burning of fossil fuels by power plants and other industrial facilities. SO2 is produced mainly from the combustion of coal and oil at electric utilities. Smaller sources include industrial processes such as extracting metal from ore, locomotives, ships, and other vehicles. Power plants using fossil fuels account for the majority of human-caused SO2 emissions.