Final answer:
The Department of Defense's policy for Unified Capabilities is defined in the DoD Unified Capabilities Reference Architecture.
Step-by-step explanation:
The Department of Defense (DoD) policy for Unified Capabilities can be found in the DoD Unified Capabilities (UC) Reference Architecture (RA). The UC RA serves as a technical blueprint for the implementation and management of UC systems within the DoD. It provides guidance on standards, interoperability, security, and other requirements related to Unified Capabilities.