A. The output lists nothing unless 10.100.0.0 has been configured as a summary rou te using the area range command.
B. If 10.100.0.0 is a subnet in area 0, the output lists one Type 3 LSA, specifically the LSA with the lower metric when comparing ABR1's and ABR2's LSA for 10.100.0.0.
C. If 10.100.0.0 is a subnet in area 0, the output lists two Type 3 LSAs, one each created by BR1 and ABR2.
D. None, because the Type 3 LSAs would exist only in the ABR's LSDBs.

A. When OSPF is enabled on a LAN interface, and the router is the only router connected to the subnet.
B.  When OSPF is enabled on a point - to -point serial link, and that router has both the higher router ID and higher interface IP address on the link.
C. When OSPF is enabled on a Frame Relay point - to - point subinterface, has the lower RID and lower subinterfa ce IP address, and otherwise uses default OSPF configuration on the interface.
D. When OSPF is enabled on a working LAN interface on a router, and the router has been elected BDR.
E. None of the other answers is correct.