What document outlines the deployment responsibilities of each unit?

The Deployment Order (DEPORD) is the correct document that outlines the deployment responsibilities of each unit. This order contains specific instructions for units that are being deployed, detailing their roles, timelines, and logistics involved in the deployment process. It serves as a crucial tool for ensuring that all units are aware of their individual responsibilities and how they fit into the larger operational picture.

The other options do not serve the same purpose as the DEPORD. For instance, the Deployment Brief may provide an overview or summary of the deployment but does not specify the detailed responsibilities of each unit. The Unit Handbook typically includes information about policies, procedures, and general guidelines for unit members, rather than specific deployment tasks. The Operational Plan (OPLAN) outlines broader operational strategies and objectives, which are not focused solely on the deployment responsibilities of individual units.