Barrington Corporation reported the following on their contribution format income statement: Sales (12,000 units) $175,000 Less: Variable expenses 100,000 Contribution margin 75,000 Less: Fixed expenses 62,500 Net operating income $ 12,500 If sales increase by 10%, net operating income will increase by what amount? Select one: A. $ 1,500 B. $ -O- C. $ 7,500 D. $30,000