You want to restore the backup of a stand-alone DB system to a new DB...

When restoring the backup of a stand-alone DB system to a new DB system, the following changes are allowed:

Use a different subnet for the new DB system(Answer B): You can select a different subnet within the same VCN or a different VCN for the new DB system, providing flexibility in network configuration.

Use a different shape for the new DB system(Answer C): You can choose a different compute shape for the new DB system, allowing you to scale the compute resources according to the requirements.

References:

OCI MySQL Database Service Backup and Restore Documentation