How do I calculate the cost of goods sold?

Required information [The following information applies to the questions displayed below. The following unadjusted trial balance is prepared at fiscal year-end for Nelson Company. Nelson company uses a perpetual inventory system. It categorizes the following accounts as selling expenses: Depreciation Expense-Store Equipment, Sales Salaries Expense, Rent Expense-Selling Space, Store Supplies Expense, and Advertising Expense. It categorizes the remaining expenses as general and administrative. NELSON COMPANY Unadjusted Trial Balance January 31 Debit Credit Cash $ 26,750 Merchandise inventory 13,500 Store supplies 6,000 Prepaid insurance 2,300 Store equipment 42,800 Accumulated depreciation- Store equipment $ 17,300 Accounts payable 16,000 Common stock 5,000 Retained earnings 35,000 Dividends 2,050 Sales 115,900 Sales discounts 1,800 Sales returns and allowances 2,100 Cost of goods sold 38,000 Depreciation expense-Store 0 equipment Sales salaries expense 13,550 Office salaries expense 13,550 Insurance expense 0 Rent expense-Selling space 8,500 Rent expense-Office space 8,500 Store supplies expense 0 Advertising expense 9,800 Totals $189,200 $189, 200 Additional Information: a. Store supplies still available at fiscal year-end amount to $1,650. b. Expired insurance, an administrative expense, is $1,400 for the fiscal year. c. Depreciation expense on store equipment, a selling expense, is $1,550 for the fiscal year. d. To estimate shrinkage, a physical count of ending merchandise inventory is taken. It shows $10,700 of inventory is still available at fiscal year-end