You are responsible for an e-commerce site. The site is hosted in a cluster. Which of the following techniques would be best in ensuring availability?

Load balancing the cluster will prevent any single server from being overloaded. And if a given server is offline, other servers can take on its workload.
Option VPN concentrator is incorrect. A VPN concentrator, as the name suggests, is used to initiate virtual private networks (VPNs).
Aggregate switching is incorrect. Aggregate switching can shunt more bandwidth to the servers but won’t mitigate the threat of one or more servers being offline.
Option SSL accelerator is incorrect. SSL accelerators are a method of offloading processor-intensive public-key encryption for Transport Layer Security (TLS) and Secure Sockets Layer (SSL) to a hardware accelerator.