Which of the following provides the BEST application availability and is easily expanded as demand grows?

A.
Server virtualization

B.
Load balancing

C.
Active-Passive Cluster

D.
RAID 6

Explanation:
Load balancing is a way of providing high availability by splitting the workload across multiple computers.
Incorrect Answers:
A: Virtualization is the foundation for cloud computing. You cannot have cloud computing without virtualization. It makes it possible by abstracting the hardware and
making it available to the virtual machines. The abstraction is done through the use of a hypervisor, which can be either Type I (bare metal) or Type II (hosted).
C: Active-Passive cluster will provide application availability, but is not as easily expanded as load balancing.
D: RAID or redundant array of independent disks (RAID). RAID allows your existing servers to have more than one hard drive so that if the main hard drive fails, the
system keeps functioning.

Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, pp 234-235