Refer to the exhibit.

 In OSPF (Open Shortest Path First), the Hello interval is a critical parameter for OSPF neighbor formation. It defines the frequency at which Hello packets are sent on an OSPF interface. For two OSPF routers to become neighbors, they must have matching Hello and Dead intervals. In the provided configuration, Router 1 has a hello-interval of 1 second while Router 2 has a hello-interval of 2 seconds. Adjusting them to match will reestablish the OSPF neighbor relationship between Router 1 and Router 2. References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) - Cisco