Determine whether the study depicts an observational study or an experiment Sixty college students are divided into two groups One group is exposed to rock music while studying The other is not After one week both groups are questioned about their scores on final mathematical examinations Is the study an observational study or an experiment OA The study is an experiment because the researchers control one variable to determine the effect on the response variable OB The study is an observational study because the researchers control one variable to determine the effect on response variable OC The study is an observational study because the study examines individuals in a sample but does not try to influence the response variable OD The study is an experiment because the study examines individuals in a sample but does not try to influence the variable of interest