4. Use this inventory information for the month of June to answer the following question. June 1 Beginning 20 units @ $10 inventory 5 Purchase 60 units @ $18 1 40 units 4 2 Purchase 30 units @ $22 1 Sale Assuming that a periodic inventory system is used, what is cost of goods sold on a FIFO basis? (4 Points) (Please show your computation in the blank space below) a $840 b. $1,380 c. S560 d. $660