Which of the following statements describes an element of process costing systems? A. Costs are accumulated by job. O B. The total units accounted for equals the sum of equivalent units in ending work in process and equivalent units completed and transferred out. C. Direct material costs are traced to individual units of production. O D. Total conversion costs include direct labor and manufacturing overhead costs included in beginning inventory and added to production during the period O E. For current period calculations, the percentage of completion for units in beginning work in process is used to calculate equivalent units under the weighted average method