Whether the study depicts an observational study or an experiment Professional weightlifters are randomly divided into two groups One group is given a diet of mostly protein the other is given a diet of mostly carbohydrates After 1 week each group is given a ifting test to compare strength Choose the correct description of the study OA The study is an observational study because the study examines individuals in a sample but does not try to influence the variable of interest OB The study is an experiment because the study examines individuals in a sample but does not try to influenc the variable of interest OC The study is an observational study because the researchers control one variable to determine the effect on response variable OD The study is an experiment because the researchers control one variable to determine the effect on the response variable