An Oracle instance is executing in a nondistributed configuration. The instance fails because of an operating system failure. Which background process would perform the instance recovery when the atabase is reopened ?

The System Monitor (SMON) background process is responsible for performing instance recovery when an Oracle database is restarted after an unexpected crash. PMON cleans up failed user processes, RECO resolves pending distributed transactions, ARCn archives redo logs, and CKPT signals checkpoints, making them incorrect for instance recovery.