Given the following data, calculate the cost of goods sold for the period using FIFO method. 1/1 Beginning inventory 40 units at $13 per unit 3/5 Purchases 20 units at $14 per unit 4/15 Sale 30 units at $30 per unit 5/30 Purchases 40 units at $11 per unit 11/15 Sale 50 units at $32 per unit 12/31 Ending inventory 20 units Select one: O a. $1,020 O b. $960 oc. $966 O d. $980