Which of the following is an authentication method supported by ESXi for iSCSI initiators and targets?

The correct choice for the authentication method supported by ESXi for iSCSI initiators and targets is LDAP. Lightweight Directory Access Protocol (LDAP) is widely used for directory services and can provide authentication for network resources. In the context of ESXi, LDAP can be used to authenticate users and manage access to resources like iSCSI storage.

While the other options like Kerberos, RADIUS, and Active Directory do serve distinct purposes in network authentication and management, ESXi specifically supports LDAP for iSCSI implementations. Kerberos is primarily used for secure authentication in network protocols, RADIUS is typically associated with network access control, and Active Directory serves as a directory service that can utilize multiple authentication methods, but it is not directly used as a method for iSCSI authentication in ESXi.

In summary, LDAP's capabilities to manage and authenticate user credentials align with the requirements for iSCSI access in the ESXi environment, making it the appropriate choice among the options presented.