Which of the following is NOT a security classification of jails?

In the context of jail security classifications, "Controlled security" is not an established category. The commonly recognized classifications include maximum security, medium security, and minimum security.

Maximum security facilities are designed to house the most dangerous offenders, featuring strict controls and heightened security measures. Medium security jails provide a balance, housing inmates who do not require the extreme restrictions of maximum security, while still ensuring a secure environment. Minimum security facilities are typically for non-violent offenders, with less restrictive environments and programs focused on rehabilitation.

Since "Controlled security" is not a standard term used within the jail system for categorizing security levels, it is the correct choice as the option that does not represent an actual security classification.