Which solution should a solutions architect recommend to enhance the origin security?

A medical company is running a REST API on a set of Amazon EC2 instances. The EC2 instances run in an Auto Scaling group behind an Application Load Balancer (ALB). The ALB runs in three public subnets, and the EC2 instances run in three private subnets. The company has deployed an Amazon CloudFront distribution that has the AL8 as the only origin.

Which solution should a solutions architect recommend to enhance the origin security?
A . Store a random string in AWS Secrets Manager. Create an AWS Lambda (unction for automatic secret rotation. Configure CloudFront to inject the random string as a custom HTTP header for the origin request. Create an AWS WAF web ACL rule with a string match rule for the custom header. Associate the web ACL with the ALB.
B. Create an AWS WAF web ACL rule with an IP match condition of the CloudFront service IP address ranges. Associate the web ACL with the ALB. Move the ALB into the three private subnets.
C. Store a random string in AWS Systems Manager Parameter Store. Configure Parameter Store automatic rotation for the string. Configure CloudFront to inject the random siring as a custom HTTP header for the origin request. Inspect the value of the custom HTTP header, and block access in the ALB.
D. Configure AWS Shield Advanced. Create a security group policy to allow connections from CloudFront service IP address ranges. Add the policy to AWS Shield Advanced, and attach the policy to the ALB.

View Answer

Answer: D

Explanation:

https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-suspend-resume-processes.html

it shows For Amazon EC2 Auto Scaling, there are two primary process types: Launch and Terminate. The Launch process adds a new Amazon EC2 instance to an Auto Scaling group, increasing its capacity. The Terminate process removes an Amazon EC2 instance from the group, decreasing its capacity. HealthCheck process for EC2 autoscaling is not a primary process! It is a process along with the following AddToLoadBalancer AlarmNotification AZRebalance HealthCheck InstanceRefresh ReplaceUnhealthy ScheduledActions From the requirements, Some EC2 instances are now being marked as unhealthy and are being terminated. Application is running at reduced capacity not because instances are marked unhealthy but because they are being terminated.

https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-suspend-resume-processes.html#choosing-suspend-resume