The income statement for Alex Manufacturing for 2020 is as follows: Sales (10,000 units) $ 120,000 Variable Expenses $72,000 Fixed Expenses 36.000 108.000 Operating Income $ 12,000 REQUIRED: If sales increase by 1,500. units, what will happen to the profit/operating income? a. Increase by $ 1,200. b. Increase by $ 4,800. C. Increase by $ 12,000. d. Increase by $ 7,200