The substance that causes the worst air pollution is

Options

A. sulphur dioxide
B. carbon dioxide
C. carbon monoxide
D. smoke

Answer

C

Explanation

Carbon monoxdde (CO)- is a colorless, odorless, non-irritating but very poisonous gas. It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide.