Which of the following can be done by Auto Scaling?

Answer options:

A.Launch EC2 instances when CPU utilization is above the threshold.
B.Terminate EC2 instances when CPU utilization is below the threshold.
C.Increase the instance size when utilization is above the threshold.
D.Decrease the instance size when utilization is below the threshold.

Answer - A and B
Options A and B are CORRECT because Auto Scaling can launch or terminate instances based on CPU utilization.
Options C and D are incorrect because Auto Scaling cannot increase or decrease the instance size based on CPU utilization. It will launch the instances based on the launch configuration.
As per the AWS documentation, below is what can be done with Auto Scaling. You can only scale horizontally and not vertically.
Scale-out Amazon EC2 instances seamlessly and automatically when demand increases.
Shed unneeded Amazon EC2 instances automatically and save money when demand subsides.
Scale dynamically based on your Amazon CloudWatch metrics or predictably according to a schedule that you define.
Replace unhealthy or unreachable instances to maintain the higher availability of your applications.
Receive notifications via Amazon Simple Notification Service (Amazon SNS) to be alerted when you use Amazon CloudWatch alarms to initiate Auto Scaling actions or when Auto Scaling completes an action.
Run On-Demand or Spot Instances, including those inside your virtual private cloud (VPC) or high-performance computing (HPC) clusters.
If you’re signed up for the Amazon EC2 service, you’re already registered to use Auto Scaling and can begin using the feature via the API or command-line interface.
For more information on Auto Scaling, please visit the link
https://aws.amazon.com/autoscaling/