d. Assuming that you did find an association between marital status and cholesterol levels, would this association mean that marital status caused a different cholesterol level? This was an observational study, from which you can conclude causality. Can you think of a confounding factor? O A. One possible confounder is age. For example, the "Never married" may tend to be young, and youth may cause the low cholesterol. O B. One possible confounder is income. For example, the "Married" may tend to have less expendable income and eat less healthy food, and this may cause high cholesterol. O C. One possible confounder is weight. For example, the "Never married" may tend to be heavier, and this may cause the high cholesterol