Davis Ltd employs a process costing system in which direct materials are added at the beginning of the process. Direct material costs from the prior period for beginning work in process are $8,000. The current period's direct material costs total $56,000. The company began the period with 500 units, 60% complete, started 9,500 units, and finished the period with 500 units, 50% complete. Using the weighted average method, the direct material cost per equivalent unit for the period is: a. $6.73 b. $5.46 c. $6.40 d. $5.60