Which of the following is true of a committed fixed cost?

a.A committed fixed cost is used to calculate the contribution margin.

b.A committed fixed cost changes in direct proportion to changes in output.

c.It is difficult to change a committed fixed cost quickly.

d.All of these choices are correct.

Which of the following businesses uses a process costing system?

a.A dental clinic

b.A refinery

c.A printing business

d.An interior designing firm

e.An automobile service center