フリー問題

問題文

Two area border routers are to carry an OSPF virtual link between them and one of the two sits on the backbone. Under which area is the virtual link written?

選択肢

1. Under the crossed area on each of the pair that the link joins
2. Under the backbone on the one that already reaches it
3. Under the backbone on each of the pair that the link joins
4. Under the crossed area on the one of the pair that stands off the backbone