The correct answer is (b) Lead.
Lead is a heavy metal that is toxic to humans and animals. It can cause a variety of health problems, including brain damage, kidney damage, and reproductive problems. Lead is found in automobile exhaust because it is used in the manufacture of gasoline. When gasoline is burned, lead is released into the air. Lead can be inhaled or ingested, and it can accumulate in the body over time.
Copper is a metal that is essential for human health. It is found in many foods, and it is also used in some medicines. Copper is not considered to be a toxic metal, but it can be harmful if it is consumed in large amounts.
Cadmium is a metal that is also found in automobile exhaust. Cadmium is toxic to humans and animals, and it can cause a variety of health problems, including kidney damage, bone disease, and cancer.
(d) None of the above is not the correct answer because lead is the most toxic metal pollutant of automobile exhaust.