An accounting course is taught in two classes per week for one hour and fifty minutes each. The classes are held in a building with 36 classrooms that are used for a variety of courses. The building has an advanced monitoring system which allows electricity costs to be determined for each classroom and for each course. If the cost object is the accounting course, which of the following is an indirect cost?
Group of answer choices

The cost of the preparation of the exam papers for this course.

The course Instructor's salary for teaching the course (he only teaches this one course).

The salary of the building's custodian.

The electricity cost for the course.