Below is a contribution format income statement for last month when Hill Corp. made and sold 10,000 units. Sales (10,000 units)...................$1,000,000 Variable Expense........ Contribution Margin........ Fixed Expense......... Net operating income... ..600,000 .400,000 ..250,000 ..150,000 If sales increase by 100 units, net operating income should increase by: Numeric Response