What type of order establishes a tentative C-Day for deployment operations?

The correct answer involves a "Warning" order, which is a preliminary notice that indicates the possibility of deployment operations. This type of order establishes a tentative timeline, also referred to as a C-Day, which serves as an initial checkpoint for planning and preparing for upcoming actions.

A Warning order typically communicates the intent to deploy and sets the necessary conditions for units to begin preparations, without committing them to immediate action. This allows for flexibility and time to coordinate logistics, readiness, and other operational aspects as the situation develops.

In contrast, an Alert order signifies that forces must be prepared to deploy but does not set a specific timeline; a Deployment Order confirms the actual order to deploy, specifying the exact actions required; and a Mission Order generally provides detailed instructions for executing a specific mission once a deployment has been established. Thus, the Warning order is crucial for initiating the process without making definitive commitments too early.