What command is used to disable the OSPF process on a router?

To disable the OSPF (Open Shortest Path First) routing process on a router, the correct command is typically issued in the router's configuration mode, and it correctly employs the use of the 'shutdown' command specific to the OSPF process.

This command stops the OSPF routing process completely, which means that the router will no longer send or receive OSPF routing updates for its interfaces that are participating in OSPF. Disabling the OSPF process can be useful for maintenance, troubleshooting, or when reconfiguring routing protocols.

In contrast, the other options do not correspond to the proper syntax or functionality recognized in Cisco IOS for managing OSPF. For instance, 'no ospf' is not a valid command and would not execute correctly, while 'disable ospf' and 'stop ospf' do not match the established terminology used in Cisco router command syntax for OSPF management. Understanding the correct syntax is essential for network administrators to effectively manage routing protocols.