Tier II Company uses a periodic inventory system. Details for the inventory account for the month of January, 2008 are as follows:

Units Per unit price Total

Balance, 1/1/08 200 $5.00 $1,000

Purchase, 1/15/08 100 5.30 530

Purchase, 1/28/08 100 5.50 550

An end of the month (1/31/08) inventory showed that 120 units were on hand.

13. How many units did the company sell during January, 2008?

a. 80

b. 120

c. 200

d. 280