Cheyenne Corp. just began business and made the following four inventory purchases in June: June 1 132 units $920 June 10 176 units 1370 June 15 176 units 1480 June 28 132 units 1160 $4930 A physical count of merchandise inventory on June 30 reveals that there are 180 units on hand. The inventory method which results in the highest gross profit for June

a. is not determinable.

b. the average cost method.

c. the FIFO method.

d. the LIFO method.