Explanation/Reference:
A: Note: If some activity you want to perform requires you to temporarily disable regularly scheduled backups, you can do so by removing the scheduling information from the system-wide /etc/crontab file.
C: You can use the dbaascli utility to restore from the most recent backup and perform complete recovery on a database deployment hosting a single-instance database:
1. Connect as the opc user to the compute node.
2. Start a root-user command shell:
$ sudo -s
#
3. Restore the most recent backup and perform complete recovery using the orec subcommand of the dbaascli utility:
# dbaascli orec --args -latest
The restore and recover process performs these steps:
Shuts down the database

Extracts and restores configuration files

Prepares for recovery

Performs the recovery

Restarts the database instance after recovery

1. Exit the root-user command shell:
# exit
$
References: Using Oracle Database Cloud Service (February 2017), page 6-23
https://docs.oracle.com/en/cloud/paas/database-dbaas-cloud/csdbi/using-oracle-database-cloud- service.pdf