Unknown In a study in the UK, an association was found between the sale of antiarrhythmic drug and an increase in deaths due to asthma. This is an example of A Ecological study B Cohort study C Case reference study D Experimental study 💡 Explanation In a study in the UK, an association was found between the sale of antiarrhythmic drug and an increase in deaths due to asthma. This is an example of ✓ Correct Answer: A. Ecological study