Tailgating, also known as piggybacking, is the act of an unauthorized individual following closely behind an authorized person to gain entry into a restricted area without their own valid access credentials. In this scenario, the badge readers are meant to control building access, but unauthorized individuals are gaining access by simply following authorized employees who use their badges to open doors. This practice compromises the security of the building and allows unauthorized people to roam the hallways. To prevent tailgating, employees should be trained to be vigilant about not allowing unauthorized individuals to follow them through access-controlled doors. Additionally, security measures like mantraps or turnstiles can be implemented to prevent tailgating incidents.

unauthorized individuals roaming the hallways = CompTIA's mental ward.

C. Tailgating

C. Tailgating

C,Tailgating -- is a type of physical security breach in which an unauthorized person follows an authorized individual to enter secured premises.