B. This is the sales level of second quarter. See the correct answer for a complete explanation.

C. To solve these questions we use the formula for the physical flow of goods:

　　Beginning Inventory + Units Produced - Units Sold = Ending Inventory

Beginning inventory for the second quarter is 20% of the second quarter sales, or 1,600 units. The ending inventory for the second quarter is 20% if the third quarter sales, or 2,400 units. Plugging numbers into the formula we will get the following:

　　1,600 + Units Produced - 8,000 = 2,400

　　Solving for Units Produced, we get Units Produced = 8,800.

D. This answer is incorrect. See the correct answer for a complete explanation.