Application deployment typically involves making a software application available for use, often involving
downtime or unavailability of the application. The description of the project manager notifying users about the
application being unavailable for a certain period aligns with standard practices during deployment phases.
The other options, such as rollback plans, validation checks, and maintenance window schedules, although
important, do not directly indicate the action of making an application available for use, as described in the
scenario.