1670 Vaughn's Place recorded the following data: Units Date Received Sold On Hand Unit Cost 1/1 Inventory 640 $2.40 1/8 Purchase 1030 1670 3.00 1/12 Sold 1230 440 The weighted-average unit cost of the inventory at January 31 is: $2.77 $3.40 O $2.67 $2.40