athletes who stretch before working out non-athletes who stretch before working out athletes who do not stretch before working out non-athletes who do not stretch before working out
I gave my students this multiple choice question: Stretching is considered an important step before engaging in sports. In an investigation to see whether stretching before physical exertion reduces sports injuries, who would the control group most likely be?

Only one answer is correct among these 4 choices:
- athletes who stretch before working out
- non-athletes who stretch before working out
- athletes who do not stretch before working out
- non-athletes who do not stretch before working out

Could you tell me which one is correct?

athletes who do not stretch before working out