Dr Fletcher Is Interested in Whether Joining a Fraternity/sorority Causes

Multiple Choice

Dr. Fletcher is interested in whether joining a fraternity/sorority causes people to become more concerned about their attractiveness and appearance. He recruits a group of 55 freshmen (25 males, 30 females) who are planning to go through fraternity/sorority recruitment on his campus. After they join, he gives them a measure of attractiveness concern/appearance concern (the Body Concern Scale) .
If Dr. Fletcher is interested in a causal relationship between joining a fraternity/sorority and attractiveness/appearance concern, why doesn't he conduct a true experiment?

A) It is not possible to study private organizations, like fraternities/sororities.
B) It is not possible to measure body concern.
C) He was unable to recruit an equal number of males and females.
D) He was unable to randomly assign participants to join a fraternity/sorority.