Option C is the correct choice. The commands copy sftp://[email protected]/backup.cfg bootflash:///backup.cfg vrf management followed by configure replace bootflash:///backup.cfg will copy the backup configuration file from the SFTP server to the switch's bootflash and then replace the running configuration with the backup file without requiring a restart of the switch. This process is known as configuration replace and is a feature that allows for the replacement of the entire running configuration with a new one provided by the user1.
References: The procedure for performing a configuration replace on Cisco Nexus 9000 Series Switches can be found in the Cisco documentation1. It is important to ensure that the backup configuration file is a valid running configuration file and that the switch has connectivity to the SFTP server through the mgmt0 interface. The configure replace command intelligently calculates the difference between the current running configuration and the user-provided configuration, applying only the necessary changes