Refer to the exhibit. All interfaces are configured with duplex auto and ip ospf network broadcast. Which configuration allows routers R14 and R86 to form an OSPFv2 adjacency and act as a central poin

Question

Exhibits

Options

• AR14# interface Loopback0 ip ospf 10 area 0 interface FastEthernet0/0 ip address 10.73.65.65 255.255.255.252 ip ospf network broadcast ip ospf 10 area 0 ip mtu 1500 router ospf 10 router-id 10.10.1.14 ip ospf priority 255 network 10.10.1.14 0.0.0.0 area 0 R86# interface Loopback0 ip ospf 10 area 0 interface FastEthernet0/0 ip address 10.73.65.66 255.255.255.252 ip ospf network broadcast ip ospf 10 area 0 ip mtu 1500
• BR14# interface FastEthernet0/0 ip address 10.73.65.65 255.255.255.252 ip ospf network broadcast ip ospf priority 255 ip mtu 1500 router ospf 10 router-id 10.10.1.14 network 10.10.1.14 0.0.0.0 area 0 network 10.73.65.64 0.0.0.3 area 0 R86# interface FastEthernet0/0 ip address 10.73.65.66 255.255.255.252 ip ospf network broadcast ip mtu 1500 router ospf 10 router-id 10.10.1.86 network 10.10.1.86 0.0.0.0 area 0 network 10.73.65.64 0.0.0.3 area 0
• CR14# interface FastEthernet0/0 ip address 10.73.65.65 255.255.255.252 ip ospf network broadcast ip ospf priority 0 ip mtu 1500 router ospf 10 router-id 10.10.1.14 network 10.10.1.14 0.0.0.0 area 0 network 10.73.65.64 0.0.0.3 area 0 R86# interface Loopback0 ip address 10.10.1.86 255.255.255.255
• DR14# interface FastEthernet0/0 ip address 10.73.65.65 255.255.255.252 ip ospf network broadcast ip ospf priority 0 ip mtu 1500 router ospf 10 router-id 10.10.1.14 network 10.10.1.14 0.0.0.0 area 0 network 10.73.65.64 0.0.0.3 area 0 R86# interface FastEthernet0/0 ip address 10.73.65.66 255.255.255.252 ip ospf network broadcast ip mtu 1400 router ospf 10 router-id 10.10.1.86 network 10.10.1.86 0.0.0.0 area 0 network 10.73.65.64 0.0.0.3 area 0

• A
  6% (2)
• B
  79% (26)
• C
  12% (4)
• D
  3% (1)

Explanation

Option B is correct because it properly configures R14 with ip ospf priority 255 at the interface level, guaranteeing it wins the Designated Router (DR) election on the broadcast segment - making it the central point for OSPF information exchange. Both routers also correctly advertise the shared /30 subnet (10.73.65.64/30) under router ospf, ensuring a valid adjacency forms.

Option A fails because ip ospf priority 255 is placed under the router ospf process rather than the interface - OSPF priority is an interface-level command (ip ospf priority), so it has no effect there. R86 also lacks a network statement covering the shared subnet, so it wouldn't participate in OSPF on that segment.

Option C fails immediately: ip ospf priority 0 explicitly prevents a router from ever becoming DR or BDR, which directly contradicts the requirement to be a "central point." R86's configuration is also incomplete.

Option D has two fatal problems: R14 again uses priority 0 (can't be DR), and R86 uses ip mtu 1400 while R14 uses ip mtu 1500 - an MTU mismatch causes OSPF to stall in ExStart/Exchange state, preventing a full adjacency.

Memory tip: Think of it as "P-M-N" - Priority must be on the interface (not the process), MTU must match on both sides, and Network statements must cover the shared subnet. Any one of these broken = no adjacency or no DR.

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