Which of the following conditions will prevent an OSPF adjacency from reaching the full state?

Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (OSPF Neighbor Formation Process):

A (Correct):

“An MTU mismatch will cause OSPF adjacency to stall in ExStart state.”

B (Correct):

“Subnet mismatch prevents OSPF neighbor discovery as Hello packets are not accepted.”

D (Correct):

“Area ID mismatch results in dropped Hello packets and no adjacency.”

Incorrect options:

C: If the system interface is not included, OSPF will not even attempt neighbor formation; this isn’t an adjacency issue but rather a configuration issue.

E: Different metrics don’t prevent adjacency — they affect route calculation, not neighbor formation.

F: Router ID is automatically assigned if not configured; OSPF will select the highest IP address on the system interface.

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