Department S had 500 units 74% completed in process at the beginning of the period, 8,800 units completed during the period, and 1,000 units 53% completed at the end of the period. What was the number of equivalent units of production for the period for conversion if the first-in, first-out method is used to cost inventories? Assume the completion percentage applies to both direct materials and conversion cost. Oa. 3,960 O b. 9,960 O c. 8300 O d. 8,430