Which three OSPF routers are the only routers that may perform summarization with the current network layout?

Refer to the exhibit. Which three OSPF routers are the only routers that may perform summarization

with the current network layout? (Choose three.)

A.
Router 2

B.
Router 3

C.
Router 4

D.
Router 5

E.
Router 7

F.
Router 8