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 $ 30,000 Variable expenses 16,500 Contribution margin 13,500 Fixed expenses 7,830 Net operating income $ 5,670 7. If the variable cost per unit increases by $1, spending on advertising increases by $1,200, and unit sales increase by 140 units, what would be the net operating income?