Suppose a firm uses workers and office space to produce output. The firm is locked into a year-long lease on its office space, but it can easily vary the number of employee hours it uses each day. The firm faces:
A. variable costs for office space and fixed costs for labor.
B. fixed costs for office space and variable costs for labor.
C. fixed costs for both office space and labor.
D. variable costs for both office space and labor.