Which of the following statements is true regarding fixed and variable costs? O a. Both costs are constant when considered on a per-unit basis. O b. Variable costs are constant in total, and fixed costs vary in total. O c. Fixed costs are constant in total, and variable costs are constant per unit. O d. Both costs are constant when considered on a total basis.

Which of the following statements is true regarding fixed and variable costs? a. Both costs are constant when considered on a per-unit basis. b. Variable costs are constant in total, and fixed costs vary in total. c. Fixed costs are constant in total, and variable costs are constant per unit. d. Both costs are constant when considered on a total basis