Supply the missing data in each independent case. Unit sales Sales revenue Variable cost per unit Contribution Margin Fixed costs Operating income Unit contribution margin Break-even point (units) Margin of Safety Case 1 700 42,000 45 ? 7,500 ? Case 2 300 ? 1 1,200 ? 100 ? ? Case 3 ? ? 15 ? 60,000 5,000 1,000 Case 4 ? 58,000 ? ? 1 30,000 -1,000 Case S 2 40,000 10,000 ? ? 2 ? 600