An Administrator Believes That the Placement of Motivational Posters on the Walls

An administrator believes that the placement of motivational posters on the walls in classrooms of academic buildings will lead to increased GPAs (grade point averages) at his school. To test his theory, he randomly assigns certain classrooms within the College of Liberal Arts and Sciences to have the posters while others do not. None of the remaining four academic colleges have any posters placed in their classrooms. What is the independent variable in this study?

A) academic college
B) classroom wall hangings
C) gender of the student
D) grade point average