SO2 as pollutant can be controlled by I. Using solar energy, nuclear energy, hydroelectric energy. II. Low Sulphur fuels, natural gas. III. Desulphonation of high-Sulphur coal and oil before burning by FGD IV. Using water under high pressure .            Correct methods are

SO2 in the atmosphere is due to burning of Sulphur containing fossil fuel S+O2→SO2 and from smelting and roasting of sulphides, CuFeS2+O2→Cu2O+FeO+SO2 content can be controlled by using alternate source of energy for burning,  as nuclear energy, solar energy, hydroelectric energy.