Kenney Co. uses process costing to account for the production of canned energy drinks. Direct materials are added at the beginning of the process and conversion costs are incurred uniformly throughout the process. Equivalent units have been calculated to be 19,200 units for materials and 16,000 units for conversion costs. Beginning inventory consisted of $11,200 in materials and $6,400 in conversion costs. April costs were $57,600 for materials and $64,000 for conversion costs. Ending inventory still in process was 6,400 units (100% complete for materials, 50% for conversion). The cost per equivalent unit for conversion costs using the weighted average method would be

a. $4.00

b. $4.40

c. $1.10

d. $8.70