Which of the following terms described as an OSPF router with interfaces connected to the backbone area and to at least one other area?

(A) Backbone area
(B) Internal router
(C) Backbone router
(D) Area Border Router

Area Border Router is the correct answer.

You should be familiar with the following terms for the CCNA:

• Area Border Router (ABR) – An OSPF router with interfaces connected to the backbone area and to at least one other area.
• Backbone router – A router connected to the backbone area (includes ABRs).
• Internal router – A router in one area (not the backbone area)
• Area – A set of routers and links that shares the same detailed LSDB information, but not with routers in other areas, for better efficiency.
• Backbone area – A special OSPF area to which all other areas must connect—area 0.
• Intra-area route – A route to a subnet inside the same area as the router.
• Interarea route – A route to a subnet in an area of which the router is not a part.