A principal wanted to survey students who took a standardized college entry exam about how prepared they felt for the exam. The principal put together a bag of marbles. There was 1 marble for each...

Extracted text: A principal wanted to survey students who took a standardized college entry exam about how prepared they felt for the exam. The principal put together a bag of marbles. There was 1 marble for each student, and 20 of the marbles were red. Each student chose a marble, and those who chose the red marbles took the survey. Which sampling method was used? O cluster sampling O simple random sampling stratified random sampling O systematic random sampling