Department S had 500 units 74% completed in process at the beginning of the period, 8,000 units completed during the period, and 1,000 units 39% completed at the end of the period. Assume the completion percentage applies to both direct materials and conversion costs, and the first-in-first-out cost flow method is used. The conversion equivalent units of production for the period are

a. 7,500

b. 9,020

c. 8,020

d. 7,630