Which OSPF neighbor state applies only to manually configured neighbors on a NBMA network?

The Attempt state is unique to OSPF neighbors on Non-Broadcast Multi-Access (NBMA) networks where neighbors are manually configured. In this state, the router sends Hello packets to a neighbor from which it has not yet received any Hello packets within the HelloInterval. This state signifies that the router is actively trying to establish contact with a neighbor it knows about (due to manual configuration) but hasn't heard from yet. The Init state indicates that a router has received a Hello packet from a neighbor, but the receiving router's ID was not included in the received Hello packet's Neighbor field. The 2-Way state means bidirectional communication has been established. Exstart and Exchange are part of the database synchronization process, occurring after the 2-Way state. These states apply to all OSPF network types, whereas Attempt is specific to manually configured NBMA neighbors.