The correct answer is D. SO2.
Sulfur dioxide
(SO2) is a major gaseous pollutant of the thermal power station. It is a colorless gas with a strong, irritating odor. SO2 is formed when sulfur-containing fuels, such as coal and oil, are burned. It is also released from volcanoes and other natural sources.SO2 can cause a variety of health problems, including respiratory problems, heart disease, and cancer. It can also damage plants and animals. SO2 can also contribute to acid rain, which can damage forests and lakes.
To reduce SO2 emissions, power plants can use scrubbers to remove the sulfur from the smoke before it is released into the atmosphere. They can also switch to fuels that do not contain sulfur, such as natural gas.
H2S is hydrogen sulfide. It is a colorless gas with a rotten egg smell. H2S is toxic and can cause death if inhaled in high concentrations. It is also flammable.
NH3 is ammonia. It is a colorless gas with a strong, pungent odor. NH3 is used in fertilizers, explosives, and other products. It is also a major component of natural gas.
NO2 is nitrogen dioxide. It is a reddish-brown gas with a sharp, irritating odor. NO2 is a major component of smog. It can cause respiratory problems and other health problems.
All of these gases can be harmful to human health and the environment. However, SO2 is the most common and harmful gaseous pollutant from thermal power stations.