Refer to the exhibit.
Why is the prefix 1.1.1.1/32 not present in the routing table of R1?
A.
There is a duplicate router ID.
B.
There is a subnet mask mismatch on Ethernet0/0.
C.
The router LSA has an invalid checksum.
D.
There is an OSPF network type mismatch that causes the advertising router to be unreachable.
A common problem when using Open Shortest Path First (OSPF) is routes in the database don’t
appear in the routing table. In most cases OSPF finds a discrepancy in the database so it doesn’t
install the route in the routing table. Often, you can see the Adv Router is not-reachable message
(which means that the router advertising the LSA is not reachable through OSPF) on top of the
link-state advertisement (LSA) in the database when this problem occurs
Error : adv router is not-reachable
Reason 1: Network Type Mismatch
(It is only option can choose)
Reason 2: Wrong Address Assignment in Dual Serial Link Setup
Reason 3: One Side of Point-to-Point Link Included in Wrong Majornet or Subnet
Reason 4: One Side Is Unnumbered and the Other Side Is Numbered
Reason 5: Broken PVC in Fully Meshed Frame Relay Environment
Reason 6: Forwarding Address Known via an External Route
Reason 7: Distribute List Is Blocking the Routes