Barley Enterprises has budgeted unit sales for the next four months as follows:

October

4,800 units

November

5,800 units

December

6,400 units

January

5,200 units

The ending inventory for each month should be equal to 15% of the next month's sales in units. The inventory on September 30 was below this level and contained only 600 units.

The desired ending inventory in units for December is:

a. 960.

b. 780.

c. 690

d. 870