determine whether the study depicts an observational study or an experiment.

a study is conducted to determine if there is a relationship between heart arrhythmias and caffeine consumption. a sample of 100 people with a hear arrhythmia are asked about their caffeine consumption.

a. the study is an experiment because the study examines individuals in a sample, but does not try to influence their variable of interest.

b. the study is an operational study because the study examines individuals in a sample, but does not try to influence the response variable.

c. the study is an observational study because the researchers control one variable to determine the effect on the response variable.

d. the study is an experiment because the researchers control one variable to determine the effect on the response variable.