The following units of an inventory item were available for sale during the year. Beginning inventory First purchase Second purchase Third purchase 10 units at $55 25 units at $60 30 units at $65 15 units at $70 The firm uses the periodic inventory system. During the year, 60 units of the item were sold. The ending inventory cost rounded to nearest dollar using average cost is Oa. $1,353 Ob. $1,263 Oc. $1,150 Od. $1,375