An Accounting Course Is Taught in Two Classes Per Week

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.There are 15 other courses taught in the Accounting Department at this university.If the cost object is the accounting course,which of the following is a direct cost?

A) The course Instructor's salary for teaching the course (he only teaches this one course) .
B) The property taxes on the land and classroom building.
C) The salary of the building's custodian.
D) The Accounting Department's secretary salary.