NorthCo's most recent income statement is shown below. Prepare a new contribution margin income statement under each of the following conditions (consider each case independently): a. The sales volume increases by 100 units. b. The sales volume decreases by 100 units. c. The sales volume is 8,000 units. d. Fixed costs decreases by $5,000. Total Per Unit (a) (b) (c) (d) Sales $420,000 $35 Variable costs 240,000 20 Contribution margin 180,000 $15 Fixed costs 140,000 Operating income (loss). $40,000