What does the OSPF LSA Type 3 summarize?

A.
the interfaces and neighbors of routers

B.
the router IDs of routers from other areas

C.
an Ethernet segment

D.
topology information from other areas

Explanation:
Type 3 – Summary LSA – an Area Border Router (ABR) takes information it has learned on one of its attached areas and it can summarize it (but not by default) before sending it out on other areas it is connected to. This summarization helps provide scalability by removing detailed topology information for other areas, because their routing information is summarized into just an address prefix and metric. The summarization process can also be configured to remove a lot of detailed address prefixes and replace them with a single summary prefix, also helping scalability. The link-state ID is the destination network number for type 3 LSAs.