Which authentication method provides a centralized way to manage user identities in an organization?

Federated Identity Management is the correct answer because it allows organizations to manage user identities in a centralized manner across different systems and domains. This method facilitates single sign-on (SSO) capabilities, meaning that users can authenticate once and gain access to multiple services without needing to re-enter their credentials for each one. It simplifies the management of user identities and enhances security by allowing organizations to establish trust relationships with external partners and service providers, making it easier to control access to resources across the organization and beyond.

In contrast, Role-based Access Control is more focused on managing permissions based on user roles rather than centralizing identity management. Public Key Infrastructure is primarily concerned with creating and managing digital certificates for secure communications, and Access Control Lists are used to define who has access to resources but do not provide a centralized identity management system.