Which statement is accurate concerning the FIFO method for assigning costs in a process costing system? A. FIFO method merges costs from prior periods with costs from current periods. B. FIFO method assumes the first costs incurred are transferred out C. FIFO method assumes the first costs incurred are still in process. D. FIFO method treats units in process at the beginning of the period in the same manner as units in process at the end of the period