Which of the follwing is an example of step (step-wise) costs? A. cost of using a copy machine with respect to the number of pages copied (cost is 5 cents per page) B. cost of employee compensation with respect to production units (the emplyee is paid $ 1,000 base salary plus $ 30 per unit produced) C. cost of renting a renting a car with respect to driving distance (the rental car comes with unlimited milege). . cost of parking at an airport with respect to parking time ( paring fee goes up by $3 every 20 minutes)