When using BGP to carry external routes, what is the ideal interaction between BGP and IGP running within a Transit AS?
A. The external routes should be redistributed into an IGP.
B. The IGP should carry the routes to reach the BGP next-hops and the core subnets within the AS.
C. The IGP should carry the core subnets within the AS. Then a mutual redistribution between BGP and the IGP should be performed.
D. The external routes should be redistributed into a Link-State IGP (like OSPF or IS-IS) with filtering to reduce the size of the Link-State database.
