A municipality implements an loT device discovery scanner and finds a legacy controller for a critical internal utility SCADA service that is running firmware with

multiple vulnerabilities. Unfortunately, the controller cannot be upgraded, and a replacement for it is not available for at least a year. Which of the following is the

best action to take to mitigate the risk posed by this controller in the meantime?

A$.$ Isolate the controller from the rest of the network and constrain connectivity.

B$.$ Remove the controller from the network altogether.

C$.$ Quarantine the controller in a VLAN used for device patching from the internet.

D$.$ Configure the internet firewall to deny any internet access to or from the controller.