According to the Covariation Theory, the Decision to Close the Class

According to the covariation theory, the decision to close the class room door during an exam would be attributed to the situation based on all of the following, except

A) the professor usually leaves the door to the classroom open on non-exam days.
B) all of the other professors close the door when they are administering exams.
C) the professor closes the class room door whenever administering exams.
D) the college requires closed classroom doors.