A professor decides to perform an experiment with two of his classes. He believes that students in a hot classroom do not learn well. In one class, he leaves the room temperature at 70 degrees (normal room temperature). In another class, he turns the temperature up to 85 degrees. At the end of the semester he gives the same final exam to students from each classroom to see if one group has learned significantly more than the other. (Overall, a highly unethical study.) In this experiment, who would be the experimental group?
A) The 70-degree class.
B) Because of ethics, there was no experimental group.
C) The 85-degree class.
D) Both groups are experimental groups.