AAA Co. uses a periodic inventory system and has the following information in regard to its inventory:

Beginning inventory	500 units @ 17	$8,500
Purchase on January 25	600 units @ 18	10,800
Purchase on March 15	500 units @ 19	9,500
Purchase on October 2	700 units @ 20	14,000
Goods available for sale		$42,800

There are 900 units in ending inventory. What is the amount of the ending inventory using the FIFO method?

a. $8,500

b. $14,000

c. $19,300

d. $17,800

Explain your answer please.