The following is last month's contribution margin format income statement: Sales (20,000 units) Variable Costs Contribution Margin Fixed Costs Net Income $ 1,200,000 (400,000) 800,000 (700,000) $ 100,000 Using the degree of operating leverage, by what percentage will net income increase if sales increase 6% next year? 48% O 6% O 12.5% none of these choices O 24%