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, 22; Film Editing 11, 29, 27, 29; Abstract Art 18, 22, 21, 24. Which class has the lowest mean enrollment over the past four semesters