How Is the Ending Balance in Work in Process Inventory

How is the ending balance in Work in Process Inventory calculated for a firm that uses the weighted average method of process costing?

A) By multiplying the costs per equivalent unit by the number of equivalent units associated with ending Work in Process Inventory.
B) By subtracting the cost of goods finished and the cost of goods sold from total manufacturing costs.
C) By adding the costs of the jobs still in process at the end of the period.
D) By dividing total manufacturing costs by total equivalent units.