Mrs. Redline teaches Exploratory Topics and wanted to help her students excel on the upcoming midterm exam. She decided to test the hypothesis that completing the review packet will cause higher grades on the midterm exam. She decided to conduct an experiment. Her 3rd period class worked on the review packet during class, getting help when needed. Her 4th period class was not given a review packet. Her 2nd period class was asked to complete the review packet for homework, as previously assigned. Afterward, Mrs. Redline compared the midterm exam grades for each class. What is the treatment for this experiment? A) The school
B) The Class
C) The Packet
D) All three classes