What is the order execution?

An organization has configured Auto Scaling for hosting their application. The system admin wants to understand the Auto Scaling health check process. If the instance is unhealthy, Auto Scaling launches an instance and terminates the unhealthy instance.

What is the order execution?
A . Auto Scaling launches a new instance first and then terminates the unhealthy instance
B . Auto Scaling performs the launch and terminate processes in a random order
C . Auto Scaling launches and terminates the instances simultaneously
D . Auto Scaling terminates the instance first and then launches a new instance

Answer: D

Explanation:

Auto Scaling keeps checking the health of the instances at regular intervals and marks the instance for replacement when it is unhealthy. The ReplaceUnhealthy process terminates instances which are marked as unhealthy and subsequently creates new instances to replace them. This process first terminates the instance and then launches a new instance.