Q: Fact 1: Most carcinogens cause cancer by producing mutations in DNA. Fact 2: Lung cancer is the deadliest of all cancers. Given the two facts above, what cause production of mutations in DNA of areas such as lungs?

Choose your answer from: 1). Damages them; 2). the environment; 3). carcinogens; 4). cigarettes; 5). rays or beams; 6). smoking tobacco; 7). smoking; 8). Pollution;
The answer is:
3).