Question 4 Which of the following statements regarding fixed, mixed and variable costs is true? a. Variable costs can be represented by a straight line where costs are the same for each data point. b. Mixed costs are zero when production is equal to zero. c. Fixed costs are zero when production is equal to zero. d. Variable costs are zero when production is equal to zero. Ob Od Mixed costs are zero when production is equal to zero. Variable costs are zero when production is equal to zero. Variable costs can be represented by a straight line where costs are the same for each data point. Fixed costs are zero when production is equal to zero