Required information [The following information applies to the questions displayed below.) Oslo Company prepared the following contribution format income statement based on a sales volume of 1,000 units (the relevant range of production is 500 units to 1,500 units): Sales $ 20,000 Variable expenses 12,000 Contribution margin 8,000 Fixed expenses 6,000 Net operating income $ 2,000 4.If sales increase to 1,001 units, what would be the increase in net operating income? Increase in net operating income