The conversion cost of ending work-in-process inventory is equal to which of the following?

The conversion cost of ending work-in-process inventory is calculated as the conversion cost per equivalent unit multiplied by the conversion cost number of equivalent units. This is rooted in the definitions of conversion costs, which consist of labor and overhead expenses incurred to convert raw materials into finished products.

In the context of ending work-in-process inventory, you focus on the units that are still in production at the end of the accounting period. The conversion cost per equivalent unit represents how much it costs to translate raw materials into a completed unit, taking into account the degree of completion of those units that remain in process.

To elaborate, the formula allows for the allocation of conversion costs proportionate to the amount of work done on those units—hence multiplying by the number of equivalent units that reflect how far along those unfinished products are in the process. This provides an accurate measure of the conversion costs associated with inventory that has not yet been completed.

The focus on equivalent units is critical in process costing systems where products are treated as indistinguishable and batch processing can vary significantly. Thus, option C captures this concept perfectly, making it the correct choice.