Nonequivalent control group design is the correct answer.
The nonequivalent control group design is one of the most frequently used social research methods. In a nonequivalent control group design, we have a group that has not been exposed to an activity or treatment being compared to another group that has been. In this case, Dr. Fletcher is willing to compare a group of 55 freshmen who are planning to go through fraternity/sorority recruitment to another group of 55 freshmen who have decided not to join a fraternity/sorority.