Johnson Company had 500 units of "Tank" in its inventory at a cost of $4 each. It purchased, for $2,800, 300 more units of "Tank". Johnson then sold 400 units at a selling price of $10 each, resulting in a gross profit of $1,600. The cost flow assumption used by Johnson
a. is FIFO.
b. is LIFO.
c. is weighted average.
d. cannot be determined from the information given.