Answer : Option D

Explanation :

Lead is a naturally occurring bluish-gray metal found in small amounts in the earth’s crust. In the past, when lead was added to gasoline, breathing automobile exhaust was the major source of lead exposure for most people. Lead in the exhaust also contaminated the soil near roads. Another major source of exposure is old paint that contains lead. Lead has been found to be carcinogen. A substance that causes cancer or helps cancer grow is called a carcinogen. Several studies have looked for a link between exposure to lead in the workplace (mainly among battery workers and smelter workers) and lung cancer. Some of these studies have found a small increase in lung cancer risk. Studies have also looked at possible links between workplace exposures to lead and other cancers, including cancers of the brain, kidney, bladder, colon, and rectum.