Which of the following resiliency techniques will provide these capabilities?

A manufacturing company has several one-off legacy information systems that cannot be migrated to a newer OS due to software compatibility issues. The Oss are still supported by the vendor, but the industrial software is no longer supported. The Chief Information Security Officer (CISO) has created a resiliency plan for these systems that will allow OS patches to be installed in a non-production environment, while also creating backups of the systems for recovery .

Which of the following resiliency techniques will provide these capabilities?
A . Redundancy
B . RAID 1+5
C . Virtual machines
D . Full backups

Answer: D