Which kind of user group do you need in the Client Authentication rule in R77?

Your users are defined in a Windows 2008 R2 Active Directory server. You must add LDAP users
to a Client Authentication rule. Which kind of user group do you need in the Client Authentication
rule in R77?

A.
External-user group
B. LDAP group

C.
A group with a generic user

D.
All Users