Boxwood Company sells blankets for $40 each. The following information was taken from the inventory records during May. The company had no beginning inventory on May 1. Boxwood uses a perpetual inventory system.

Date	Blankets	Units	Cost
May 3	Purchase	9	$14
10	Sale	4
17	Purchase	11	$18
20	Sale	6
23	Sale	3
30	Purchase	11	$21

Determine the cost of goods sold for the sale of May 20 using the LIFO inventory costing method.

a. $108

b. $56

c. $54

d. $231