Which option is an example of an experiment?

A. Polling teenagers about their screen time in a day

B. Asking students in a school how much time they spend exercising

C. Testing the effect that eating organic food has on health by having
a group of people selected at random eat organic food for six consecutive months and then comparing the results with a group of people who didn't eat any organic foods during the same period

D. Recording the reaction time of participants in a study who were
asked to press a button as soon as they see a certain picture on a screen ASAP please