explain please

Cotton Corp, reported income of $42, 400 for 2008, changes occurred in several balance sheet account as follows: Additional information: During 2008, Cotton sold equipment costing $15,000 with accumulated depreciation of $16,000, for a gain $7,000. In December 2008, purchased equipment costing $70,000 with $28,000 cash and a 12% note payable of $42,000 Depreciation expense for the year was $72,000. In cement 2008 statement of cash flow, net cash used activities should be a. $2, 800 b. $16,000 c. $30,000 d.$49,000