An architect was recently hired by a power utility to increase the security posture of the company`s power generation and distribution sites. Upon review, the architect identifies legacy hardware with highly vulnerable and unsupported software driving critical operations. These systems must exchange data with each other, be highly synchronized, and pull from the Internet time sources. Which of the following architectural decisions would BEST reduce the likelihood of a successful attack without harming operational capability? (Choose two.) 

Answer options:

A. Isolate the systems on their own network
B. Install a firewall and IDS between systems and the LAN
C. Employ own stratum-0 and stratum-1 NTP servers
D. Upgrade the software on critical systems
E. Configure the systems to use government-hosted NTP servers

BE