Which of the following describes the 2N model for VM redundancy?

Which of the following describes the 2N model for VM redundancy?
A . There is one active VM and one standby VM that takes over if the active VM fails.
B . Thera are N active VMs and a pool of standby VMs that can take over if one or more active VMs fail.
C . There are N active VMs, each one paired with a standby VM that takes over if its active VM fails.
D . There are 2N active VMs deployed to support a service that needs N active VMs, with extra capacity in case one or more VMs fail.

Answer: C