Concord Corporation had 530 units of Tank in its inventory at a cost of $4 each. It purchased, for $2800, 310 more units of Tank. Concord then sold 420 units at a selling price of $10 each, resulting in a gross profit of $1740. The cost flow assumption used by Concord

cannot be determined from the information given.

is weighted average.

is FIFO.

is LIFO.