Explanation
Browser-based Authentication sends users to a web page to acquire identities using Captive Portal and Transparent Kerberos Authentication. Captive Portal is a web page that prompts users to enter their credentials. Transparent Kerberos Authentication is a method that automatically authenticates users who have a valid Kerberos ticket from the Active Directory domain controller2. UserCheck is a feature that allows users to interact with the security policy, not a method of authentication. User Directory is a component that integrates with external user databases, not a web page for authentication. Captive Portal alone is not enough to fill in the blank, as it is only one of the methods used by Browser-based Authentication.