What annotation indicates that a building check is secure?

The annotation that indicates a building check is secure is "Secure" (SEC). This designation directly communicates that the facility has been checked and verified to be safe, with no breaches or vulnerabilities present at the time of inspection. It reassures personnel that the environment is secure for operational activities and that there are no immediate threats to the security of the building.

Other options represent different statuses. For example, "All In Order" (AIO) may suggest that everything is functioning normally, but it does not specifically confirm the security of the premises. "Personnel Not Available" (PNA) indicates that there are individuals who are not present, which does not relate to building security. "Unsecured" (UNS) clearly conveys that there are issues with security, making it the opposite of what "Secure" represents. Thus, the term "Secure" (SEC) is the most precise annotation for indicating that a building check has concluded with the conclusion that all is safe and intact.