Assume that a firm has the following data for the year ended 12/31/2019: Sales: $500 Depreciation expense: $30 Interest expense: $50 Tax expense: $30 Net worth: $100 In addition, the companys net worth in 2018 was $100. Assume that in 2020, sales, cost of goods sold, and S, G, & A expenses remain the same, depreciation expense decreases, interest expense decreases, and tax expense decreases. Which of the following statements are true for the firm in 2020? I. Gross margin will decrease. II. Operating margin will increase. III. Net income will decrease. IV. Return on beginning equity will increase.