Which of the descriptions is a high-level overview of how Kerberos works?

A.
In a Kerberos environment, a user authenticates once to each service.

B.
In a Kerberos environment, a user authenticates once to a central authority.

C.
In a Kerberos environment, a user needs to type a password for each service.

D.
In a Kerberos environment, a user authenticates once to any service of its choosing and is then pre-authenticated for all other services.