What technique should be used on BGP edge routers to prevent a multi-homed autonomous
system from becoming a transit system?

A.
Advertise with a high MED value all networks that are discovered via external BGP.

B.
Remove the AS-Path information on all routes in the BGP table prior to advertising externally.

C.
Only advertise networks externally if they have been discovered via internal BGP.

D.
Use an outgoing distribution list to filter all networks not originating from inside the autonomous system.

E.
Set the no-export community attribute on all networks that are advertised externally.

F.
Set the origin code to incomplete for all networks that are discovered via external BGP.