Pesco Processing uses weighted average process-costing. All materials are introduced at the start of manufacturing, and conversion costs are incurred evenly throughout the process. The company's beginning and ending work-in-process inventories totaled 10,000 units and 15,000 units, respectively, with the latter units being 2/3 complete at the end of the period. Pesco started 30,000 units into production and completed 25,000 units. Manufacturing costs follow. Beginning work in process: Materials, $60,000; conversion cost, $150,000 Current costs: Materials, $180,000; conversion cost, $480,000 Pesco's equivalent-unit cost for conversion cost is: Select one: O a. $13.71 O b. $18.00. O c. $21.00. O d. $25.20. O e. None of the answers is correct