Students in a large statistics class were randomly divided into two groups. The first group had a midterm exam that was printed on canary paper while the second group had the exam printed on pale green paper. The exam scores of the two groups were then then compared. This experiment was not blind because:a. Students were allowed to keep their eyes open while taking the exam. b. The exam was too long. c. The students knew whether or not music was playing while they were taking the exam. d. Some of the students did not study for the exam. e. Students were randomized into the two groups.