The Boxwood Company sells blankets for $60 each. The following was taken from the inventory records during May. The company had no beginning inventory on May 1.

Date	Blankets	Units	Cost
May 3	Purchase	5	$20
10	Sale	3
17	Purchase	10	$24
20	Sale	6
23	Sale	3
30	Purchase	10	$30

Assuming that the company uses the perpetual inventory system, determine the cost of goods sold for the sale of May 20 using the LIFO inventory cost method.

a.$136

b.$144

c.$120

d.$180