Final answer:
The step in which materials, labor, and overhead are detailed is allocating the costs to the units transferred out and the units partially completed.
Step-by-step explanation:
The step in which materials, labor, and overhead are detailed is D. allocating the costs to the units transferred out and the units partially completed. This step involves assigning costs to the products that have been completed and transferred out of the production process, as well as the products that are still in process. It takes into account the direct materials, direct labor, and manufacturing overhead costs incurred during production.