Which of the following statements is most accurate? select one: a. in process costing, estimating the degree of completion of units is usually more accurate for conversion costs than for direct materials. b. the fifo method includes the cost of the beginning work in process inventory account in calculating cost per equivalent units. c. the fifo method computes equivalent units based only on production activity in the current period, ignoring the percentage of completion in beginning work in process inventory. d. the fifo method of calculating equivalent units of production merges the work and the costs of the beginning inventory with the work and the costs done during the current period. e. it is not possible for there to be a significant difference between the cost of completed units between the weighted average and the fifo methods.