Which of the Following Statements About Smoking-Related Conditions Is Correct

Which of the following statements about smoking-related conditions is correct?

A) Smoking is the second leading cause of preventable death in the world, including the United States.
B) In the United States, COPD ranks second behind ischemic heart disease the leading cause of mortality.
C) Long-term smokers have lower incidences of all-cause morbidity and mortality.
D) Smoking cessation is the most cost-effective intervention for smokers with heart disease in terms of risk reduction.