What is a common feature of access control systems?

Access control systems are designed to regulate who can enter or exit a space and often implement various methods for authentication and authorization. A prominent feature of these systems is their ability to enhance security through the use of keycards or biometric authentication. Keycards serve as a physical token that grants access when swiped or scanned, while biometric authentication relies on unique physical characteristics, such as fingerprints or facial recognition, to verify an individual's identity.

The use of keycards and biometric systems allows for a streamlined and efficient means of managing access compared to traditional manual methods. This technological integration is critical for establishing secure environments where only authorized personnel can gain entry, thus significantly reducing the risk of unauthorized access.

Other approaches, such as solely manual operation or requiring constant human oversight, are less common and can introduce vulnerabilities due to human error or oversight. Additionally, while access control systems do serve administrative purposes, their primary function is focused on physical security through restricted access rather than solely on administrative tasks. Therefore, the incorporation of keycards or biometric authentication is what makes option C the most relevant and accurate feature of access control systems.