The correct answer is A. Carbon monoxide and dioxin.
Carbon monoxide is a colorless, odorless gas that is produced when carbon is burned incompletely. It is a major pollutant of cigarette smoke and can cause a number of health problems, including heart disease, stroke, and cancer.
Dioxin is a group of toxic chemicals that are produced as byproducts of industrial processes and the burning of fossil fuels. They are also found in cigarette smoke. Dioxins can cause a number of health problems, including cancer, reproductive problems, and developmental problems.
Nicotine is a stimulant that is found in tobacco. It is addictive and can cause a number of health problems, including heart disease, stroke, and cancer. However, nicotine is not a major pollutant of cigarette smoke.
Benzene is a chemical that is found in gasoline and other petroleum products. It is also found in cigarette smoke. Benzene can cause a number of health problems, including cancer, leukemia, and anemia. However, benzene is not a major pollutant of cigarette smoke.
In conclusion, the major pollutants of cigarette smoke are carbon monoxide and dioxin.