are correct? (Choose three)

are correct? (Choose three)

A.
A transit AS has eBGP connection(s) to only one external AS.

B.
Routes between ASs are always exchanged via Ebgp.

C.
A transit AS uses an IGP like OSPF of ISIS to propagate the external networks within the transit AS.

D.
Core routers within a transit AS normally use default routing to reach the external networks.

E.
iBGP sessions can be established between non directly connected routers.

F.
Edge routers within a transit AS usually announce themselves as the next hop in the iBGP updates.