Which explanation of an Account Unit is INCORRECT?

A.
An Account Unit is the interface which allows interaction between the Secure Web Gateway and the
LDAP servers.

B.
Each Account Unit represents one or more branches of the data maintained on the LDAP server.

C.
When a query about a user is sent to the Gateway, it chooses one of the LDAP servers defined on the
Account Unit according to their priorities.

D.
An Account Unit is a 3rd party product that stores an external user Database.