Following are utilities costs for different level of machine hours: $450 for 10 hours; $540 for 12 hours : $630 for 14 hours : $720 for 16 hours. This cost is best described as Select one: a. Fixed b. None of the answers given c. Variable d. Mixed e. Direct All else being equal, a $10.00 increase in a product's variable expense per unit accompanied by a $10.00 increase in its selling price per unit will Select one: a. Increase the break-even volume. b. decrease the total contribution margin. C. None of the given answers, d. have no effect on the degree of operating leverage. e. have no effect on the contribution margin ratio