Explanation
The three authentication types that can be used to authenticate users are:
A: Local database authentication. This is the authentication type that uses the local user database on the firewall or Panorama to store and verify user credentials1.
C: Cloud authentication service. This is the authentication type that uses a cloud-based identity provider, such as Okta, PingOne, or PingFederate, to authenticate users and provide SAML assertions to the firewall or Panorama2.
E: Kerberos single sign-on. This is the authentication type that uses the Kerberos protocol to authenticate users who are logged in to a Windows domain and provide them with seamless access to resources on the firewall or Panorama3.