What unit bears the costs associated with WRM constitution after indirect mission support use?

The correct choice is the using unit because this unit is responsible for the costs incurred during the War Reserve Materiel (WRM) constitution after indirect mission support usage. The using unit is the one that directly utilizes the WRM assets, and as such, it bears the financial responsibility for maintaining and constituting these resources whenever they are activated or utilized for operations. This reflects a fundamental principle in logistics where the entity using the resources also assumes accountability for the associated costs.

Other units, such as the logistics command or storing command, may play roles in the support and management of WRM but do not directly incur the costs associated with the constitution once an asset has been identified for use by a specific mission or operation. Similarly, unit operations would be involved in the execution of the mission, but the fiscal responsibility remains with the using unit that activates the WRM resources.