A certain gene can be stimulated by chemicals in cigarette smoke, causing lung cells to metabolize the chemicals in a way that makes the cells cancerous. Yet smokers in whom this gene is not stimulated have as high a risk of developing lung cancer from smoking as other smokers do. If the statements above are true, it can be concluded on the basis of them that
A: the gene is more likely to be stimulated by chemicals in cigarette smoke than by other chemicals
B: stimulation of the gene by chemicals in cigarette smoke is not the only factor affecting the risk for smokers of developing lung cancer
C: nonsmokers have as high a risk of developing lung cancer as do smokers in whom the gene has not been stimulated
D: smokers are less likely to develop lung cancer if they do not have the gene
Choose A, B, C or D as your solution.
B