8. A factory making soft toys uses a machine on its single production line. The machine costs 2,400 per month to hire plus 10 per hour it is used. Each week up to 1,000 toys are produced and the line works anywhere between 30 and 40 hours a week. Which of the following best describes the cost of hiring the machines? Select one a. A step cost b. A variable cost C. A fied cost d. A semi-variable cost e. None of the above is correct