Which combination of actions will moot those requirements with the LEAST operational overhead?
(Choose two.)
Migrate all manual snapshots to the Amazon S3 Standard-Infrequent Access (S3 Standard-IA) storage class
Use an automated snapshot schedule to take a snapshot once each day
Create an Amazon CloudWatch billing alarm to publish a message to an Amazon Simple Notification Service (Amazon SNS) topic if the threshold is exceeded
Create a serverless AWS Glue job to run every 4 hours to describe cluster snapshots and send an email message if the threshold is exceeded
Delete manual snapshots that are not required anymore
Explanations:
Migrating snapshots to S3 Standard-IA can help reduce storage costs, but Amazon Redshift backup storage is separate and not directly applicable.
Automated snapshots help with backup, but this does not address cost reduction or notifications on backup storage charges.
CloudWatch billing alarms are specifically designed for cost tracking and can notify when backup storage charges exceed a set threshold.
Using an AWS Glue job to describe snapshots and send emails introduces unnecessary complexity and operational overhead.
Deleting manual snapshots that are no longer needed will directly reduce the backup storage costs, lowering the bill.
I estimate that the answer is:
Create an Amazon CloudWatch billing alarm to publish a message to an Amazon Simple Notification Service (Amazon SNS) topic if the threshold is exceeded