Detailed Answer
Correct answer: (A)
Because the beginning work-in-progress is 40% complete, the materials have already been added. However, as the ending work-in-progress is 20% complete, the materials have not been added. As a result, the materials were added this period only to the units that were started and completed. 85,000 units were completed during the period, but because there were 15,000 units in beginning work-in-progress, only 70,000 units were started and completed during the period.