The 2013 financial statements of Walgreen Co. reported the following information (in millions): 2013 2012 Cost of sales $51,098 $51,291 Inventories, net 6,852 LIFO reserve 2,100 1,897 7,036 The 2013 average inventory days outstanding is: OA. 48.9 days OB. 33.9 days C. 21.5 days OD. 49.6 days O E. None of the above