You are presented with the question "What can cause cancer by producing mutations in DNA?" and the following answer choices: 
- maples
 - PDAs
 - A drug.
 - copper
 - coal
 - CO 2
 - smoke
 - sponges

Now knowing that most carcinogens cause cancer by producing mutations in DNA and smoke is full of carcinogens, choose the best answer.


 

       smoke  