Income statement during three months is as follows. Income Statement

Jan Feb Mar Units sold 600 750 900 Sales 84,000 105,000 126,000 Cost of goods sold 33,600 42,000 50,400 Gross profit margin 50,400 63,000 75,600 Selling and administrative expenses: Shipping expense 8,800 10,000 11,200 Advertising expense 14,000 14,000 14,000 Salaries & commissions 21,400 25,000 28,600 Insurance 1,800 1,800 1,800 Depreciation 8,400 8,400 8,400 Total selling and administrative expense 54,400 59,200 64,000 Net income (loss) (4,000) 3,800 11,600 Required: a. What is the contribution margin of Feb b. Identify which expenses are variable, fixed, or mixed expenses. For mixed expenses, calculate variable and fixed expenses.