DrFletcher Is Interested in Whether Joining a Fraternity/sorority Causes People

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) .

-In addition to measuring the body concern of the participants who joined a fraternity/sorority both immediately before and immediately after they join,Dr.Fletcher measures them for the three weeks before and the three weeks after.This type of design is known as a/an:

A) Nonequivalent control group design
B) Nonequivalent groups interrupted time-series design
C) Interrupted time-series design
D) Multiple-baseline design