Orion Iron Corporation tracks the number of units purchased and sold throughout each year but applies its inventory costing method at the end of the year, as if it uses a periodic inventory system. Assume its accounting records provided the following information at the end of the annual accounting period, December $31.$

$3.$ Compute the cost of ending inventory and cost of goods sold under $($a$)$ FIFO, $($b$)$ LIFO, and $($c$)$ weighted average cost.

$4.$ Prepare an income statement that shows under the FIFO method, LIFO method and weighted average method.