The correct answer is 'Single sign-on (SSO)' because it allows users to authenticate once and access multiple applications without needing to log in again, thus meeting the organization's requirement for streamlined authentication across various services. 'Federated identity' refers to the linking of a user's identity across multiple distinct identity management systems, which supports SSO but is a broader concept. 'Certificate-based authentication' uses digital certificates for authentication and does not necessarily provide the SSO capability across different web applications. 'LDAP bind' is a way to authenticate against a directory service like LDAP, but it does not imply the SSO feature across multiple applications.