An organization has several production critical SCADA supervisory systems that cannot follow the normal 30-
day patching policy. Which of the following BEST maximizes the protection of these systems from malicious
software?

A.
Configure a firewall with deep packet inspection that restricts traffic to the systems

B.
Configure a separate zone for the systems and restrict access to known ports

C.
Configure the systems to ensure only necessary applications are able to run

D.
Configure the host firewall to ensure only the necessary applications have listening ports