To control administrative access to the WLC using Active Directory without concern for RBAC post- authentication, the engineer would configure a RADIUS server (option D) and a TACACS server (option E).
These servers can integrate with Active Directory to authenticate users, and once authenticated, the admin user's access level can be determined without the need for additional role-based access control configurations within the WLC. References: CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide, focusing on the integration of WLC with RADIUS and TACACS servers for administrative access control.