Suppose that you have several servers running on physical systems; each server application keeps its data on its own SAN LUN. You wish to provide failover standby for each server,but your time and hardware budget are limited. It is unlikely that all the servers will fail simultaneously.
Which approach is most suitable for this situation?

A.
Setup cluster-in -a-box.

B.
Setup virtual-to-virtual clustering between ESX Servers.

C.
Setup virtual-to-physical clustering.

D.
Setup a coldbackup server system for each application.