What feature must be implemented to avoid re-entry with the same credential?

The correct choice addresses a critical aspect of maintaining secure access control in environments that utilize credential-based entry systems. Anti-passback is a security feature designed specifically to prevent the reuse of credentials in a way that allows an individual to gain unauthorized repeated access. Essentially, it ensures that once a credential has been used to enter a secure area, it cannot be used again until the individual exits and the state is reset, thereby blocking potential attempts of sharing credentials for re-entry.

For example, in a secured building, if an employee swipes their card to enter a room, the anti-passback feature would prevent the same card from being used again until the employee has exited that room. This mechanism enhances security by preventing situations where one person could allow another unauthorized individual to enter through sharing their access credentials or by reusing them improperly.

The other areas mentioned, while relevant to security and access controls, do not specifically address the issue of preventing the same credential from being reused for re-entry. Access control generally refers to overall measures to restrict or manage user rights and permissions within a system, while redundancy checks might focus on ensuring data integrity and availability but not preventing unauthorized access. Time delays can serve as a deterrent but do not inherently block re-entry with the same credentials.