Department S had 500 units 71% completed in process at the beginning of the period, 8,400 units completed during the period, and 1,000 units 41% 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. 7,900 Ob. 8,455 Oc. 9,455 Od. 8,045