Consider each of the following scenarios and state whether or not the variable in question is a confounder, and why. a. a study of the risk of pulmonary hypertension among women who take diet drugs to lose weight. the crude relative risk of pulmonary hypertension comparing diet drug users to non-users is 17.0 and the age adjusted relative risk is 5.0. is age a confounder in this study? b. a cohort study of liver cancer among alcoholics. incidence rates of liver cancer among alcoholic men are compared to a group of non-alcoholic men. is gender a confounder in this study? c. a case-control study of the risk of beer consumption and oral cancer among men. in this study, cigarette smoking is associated with beer consumption and is a risk factor for oral cancer among both beer drinkers and nondrinkers. is cigarette smoking a confounder in this study?