Given the above OSPF network, which command will RTB use to summarize routes for the
192.168.16.0/22 supernet before injecting them into Area 0?

A.
area 10 range 192.168.16.0 255.255.252.0

B.
summary-address 192.168.16.0 255.255.252.0

C.
ip summary-address ospf 101 192.168.16.0 255.255.252.0

D.
area 0 range 192.168.16.0 255.255.252.0

E.
ip summary-address area 0 192.168.16.0 255.255.252.0

Explanation:
The area range command is used only with Area Border Routers (ABRs) which is router RT2
in this example. It is used to consolidate or summarize routes for an area. The result is that a
single summary route is advertised to other areas by the ABR. Routing information is
condensed at area boundaries. External to the area, a single route is advertised for each
address range. Only Choice A specifies the correct syntax and route summarization network
mask.