A merchandising company has beginning inventory of 50 units with a total cost of $500. The following transactions during the month of January: 1/5 bought 10 units at $11.00 each; 1/8 bought 15 units at $11.25 each; 1/15 sold 8 units for $16 each; 1/22 bought 10 units at $11.50 each and sold 12 units for $16.50 each. The ending inventory is $693.75. What inventory costing method is the company using?

FIFO

LIFO perpetual

LIFO periodic

weighted average