Many people argue that tobacco advertising plays a crucial role in causing teen-agers to start or continuesmoking. In Norway, however, where there has been a ban on tobacco advertising since 1975, smoking is atleast as prevalent among teen-agers as it is in countries that do not ban such advertising.

Which of the following statements draws the most reliable conclusion from the information above?

• ATobacco advertising cannot be the only factor that affects the prevalence of smoking among teen-agers.  
• BAdvertising does not play a role in causing teen-agers to start or continue smoking.  
• CBanning tobacco advertising does not reduce the consumption of tobacco.  
• DMore teen-agers smoke if they are not exposed to tobacco advertising than if they are.  
• EMost teen-agers who smoked in 1975 did not stop when the ban on tobacco advertising was implemented.