The correct answer is C. Adult smoking rates had been declining for more than 30 years before teens began to decline.
Explanation
The image is a scatter plot that relates smoking in parents and adolescents between 1965 and 2011; the green line represents Adults, while the blue line represents Adolescents. As a conclusion of this graph, it can be established that since 1965 Adults have been linked to cigarette consumption, while Adolescents have been related to this activity since 1992. Therefore, the correct answer is C. more than 30 years before teens will begin to reduce their rates.