The Dean of a Local College Needs to Drop One

The dean of a local college needs to drop one course from the art program.She decides to pick the course with the lowest average enrollment rate from the previous four semesters.The enrollments of three courses she is considering are Photography-30, 20, 12, and 22; Film Editing-11, 29, 27, and 29; and Abstract Art-18, 22, 21, and 24.Which class has the lowest mean enrollment over the past four semesters?

A) Photography
B) Film Editing
C) Abstract Art
D) All three classes have the same mean.