You have decided you need to change the instance type of your instances in production which are running as part of an Autoscaling Group. You currently have 4 instances in production. You cannot have any interruption in service and need to ensure 2 instances are always running during the update. Which of the below options can be chosen for this?

Answer options:

A.AutoScalingRollingUpdate
B.AutoScalingScheduledAction
C.AutoScalingReplacingUpdate
D.AutoScalingIntegrationUpdate

Answer – A
The AWS::AutoScaling::AutoScalingGroup resource supports an UpdatePolicy attribute. This is used to define how an Auto Scaling group resource is updated when an update to the CloudFormation stack occurs. A common approach to updating an Auto Scaling group is to perform a rolling update, which is done by specifying the AutoScalingRollingUpdate policy. This retains the same Auto Scaling group and replaces old instances with new ones, according to the parameters specified.
For more information on Autoscaling updates , please refer to the below link:
https://aws.amazon.com/premiumsupport/knowledge-center/auto-scaling-group-rolling-updates/