A user wants to receive an email notification when the virtual machine CPU usage enters a critical state, and again when the problem has been resolved. Which two state changes must be chosen to receive the appropriate notifications? (Choose Two.)

A.
green-yellow state change

B.
yellow-red state change

C.
red-green state change

D.
yellow-green state change

Explanation:
vSphere Basic System Administration vCenter Server 4.0 ESX 4.0 ESXi 4.0, page 235.
VMware uses colors to denote alarm severity:
Normal – green
Warning – yellow
Alert – red
You can set alarms to trigger when the state changes from green to yellow, yellow to red, red to yellow, and yellow to green.

When the virtual machine CPU usage enters a critical state, it will change from Warning (yellow) to Critical (red). When the condition has been resolved it will change from Warning (yellow) to Normal (green).