Which of the following authentication services uses a ticket granting system to provide access?

RADIUS is an AAA protocol that uses a challenge-response mechanism for authentication and does not use a ticket granting system.

LDAP is a directory access protocol used to query directory services and is not an authentication protocol with a ticket system.

TACACS+ is a Cisco AAA protocol that separates authentication, authorization, and accounting using TCP but does not use tickets.

Kerberos operates through a Key Distribution Center (KDC) that issues a Ticket Granting Ticket (TGT) upon initial authentication. The client then presents the TGT to the Ticket Granting Service (TGS) to obtain service tickets for accessing specific resources, without re-entering credentials. This ticket granting mechanism is the defining characteristic of Kerberos and distinguishes it from all other listed protocols.