A Linux SFTP server is configured for IP address 192.

Backing up the switch configuration to a remote Linux SFTP server requires using the copy command with the correct protocol (SFTP in this case), username, server IP, filename, and optionally the VRF to route management traffic.

Option A uses SCP and vrf default but the question mentions SFTP server, so SFTP protocol should be used.

Option B is a server-side command (not the switch).

Option C correctly uses copy startup-config sftp://user@192.168.1.100/switch_config.cfg vrf mgmt which backs up the startup-config via SFTP using the management VRF.

Option D is also a server-side command.

Using vrf mgmt is required because the management IP is in a separate VRF on CX switches.