Studies Have Shown That If People Can Give Up Smoking

Studies have shown that if people can give up smoking, ​

A) their risk of cardiovascular disease declines, but their risk of pulmonary disease increases.
B) their overall health risks decline reasonably quickly.
C) their risk of pulmonary disease declines, but their risk of cardiovascular disease increases.
D) their health risks never decline to the level of those who never smoked.