Correct Answer: LDAP (Lightweight Directory Access Protocol) is a software protocol for locating resources such as organizations, individuals, files, and devices in a network, typically used in both public internet and corporate intranets. SAML (Security Assertion Markup Language) is an open-standard data format for exchanging authentication and authorization data between parties, often used for single sign-on (SSO). Kerberos is a protocol for providing strong authentication for client-server applications by using secret-key cryptography, and it involves ticket-based systems for authentication. RADIUS (Remote Authentication Dial-In User Service) provides centralized Authentication, Authorization, and Accounting (AAA), and it is commonly used in network access control. OAuth 2.0 (Open Authorization 2.0) is an authorization framework that allows third-party applications to obtain limited access to a HTTP service on behalf of the user, without revealing the user's credentials, enabling functionalities such as those found in Facebook, GitHub, and other similar services.