During December, Krause Chemical Company had the following selected data concerning the manufacture of Xyzine, an industrial cleaner: Physical Units Production Flow Completed and transferred to the next department 100 Add: Ending work-in-process inventory 10 (40% complete as to conversion) Total units to account for 110 Less: Beginning work-in-process inventory 20 (60% complete as to conversion) Units started during December 90 All materials are added at the beginning or processing in this department, and conversion costs are added uniformly during the process. The beginning work-in-process inventory had $120 of raw material and $180 of conversion costs incurred. Materials added during December was $540 and conversion costs of $1,484 were incurred. Krause uses the first-in, first-out (FIFO) process-costing method. The equivalent units of production used to calculate conversion costs for December were: Select one: O a. 110 units O b. 104 units O C. 100 units O d. 92 units