A company had the following purchases during the current year:
Jan: 10 units at $ 120

Feb: 20 units at $130

May: 15 units at $140

Sep: 12 units at $150

Nov: 10 units at $160

On December 31, there were 29 units remaining in ending inventory. These 29 units consisted of 1 from March, 6 from April, 5 from June, 9 from October, and 8 from November. Using the specific identification method, what is the cost of the ending inventory?

a. $3,500.

b. $3,800.

c. $3,960.

d. $3,280.

e. $3,640.