What is one key characteristic of secure confinement?

A key characteristic of secure confinement is that it uses physical structures, such as bars or restraints, specifically designed for holding individuals in a secure manner. This feature is essential for ensuring the safety of both the individuals being confined and the staff overseeing them. Secure confinement facilities are typically designed to prevent escape and unauthorized access while maintaining a controlled environment that can manage the behavior of those incarcerated.

Other options, while they may relate to certain aspects of confinement or juvenile justice facilities, do not represent the primary characteristic defining secure confinement. For example, secure confinement is not exclusively for individuals over 18, nor is it typically situated within community centers. Additionally, while educational services may be offered in some juvenile facilities, they are not inherent to the definition of secure confinement itself. The physical security aspect is what makes option B the correct choice.