Please help me solve this problem.

Use the following financial information to find the entry you would make on an income statement for GROSS MARGIN for the year ended December 31, 2011: Gross Sales, $231,000; Sales Returns and Allowances, $7,700; Sales Discounts, $6,800; Merchandise Inventory, January 1, 2011, $55,200; Merchandise Inventory, December 31, 2011, $61,300; Net Purchases, $81,900; Freight In, $950; Salaries, $87,000; Rent, $20,600; Utilities, $1,500; Insurance, $2,350; and Income Tax, $17,350. O a. $87,700 O b. $216,500 O c. $139,750 O d. $128,800