In a cross-sectional study of 500 factory workers assessing smoking status and COPD prevalence, which statement is true?

In a cross-sectional study of 500 factory workers assessing smoking status and COPD prevalence, which statement is true?

• A. It randomizes participants to exposure groups
• B. It determines prevalence of smoking and COPD at a single point in time
• C. It determines incidence of COPD
• D. It establishes causality between smoking and COPD

Answer: (B)