AWS Config is a service that enables you to assess, audit, and evaluate the configurations of your AWS resources. By creating a Config rule, you can automatically check whether your Amazon EBS volumes are encrypted and flag those that are not, with minimal cost and configuration effort.
AWS Config Rule: AWS Config provides managed rules that you can use to automatically check the compliance of your resources against predefined or custom criteria. In this case, you wouldcreate a rule to evaluate EBS volumes and determine if they are encrypted. If a volume is not encrypted, the rule will flag it, allowing you to take corrective action.
Operational Overhead: This approach significantly reduces operational overhead because once the rule is in place, it continuously monitors your EBS volumes for compliance, and there's no need for manual checks or custom scripting.
Why Not Other Options?:
Option A (Lambda with API calls and EventBridge): While this can work, it involves writing and maintaining custom code, which increases operational overhead compared to using a managed AWS Config rule.
Option B (API calls on Fargate): Running API calls on Fargate is more complex and costly compared to using AWS Config, which provides a simpler, managed solution.
Option C (IAM policy with Cost Explorer): This option does not directly enforce encryption compliance and involves manual intervention, making it less efficient and more prone to errors.
AWS References:
AWS Config Rules- Overview of AWS Config rules and how they can be used to evaluate resource configurations.
Amazon EBS Encryption- Information on how to manage and enforce encryption for EBS volumes.

Concurrency Scaling allows Amazon Redshift to add transient capacity automatically to handle bursts in concurrent queries. This is ideal for scenarios with predictable surge periods, such as end-of-month reporting.
It improves performance without manual resizing or cluster modification and without affecting availability.
Resizing requires manual intervention and potential downtime, and Redshift Spectrum is designed for querying data in S3, not for solving concurrency issues.

The best design is todecouple the two stages with SQS queuesand scale each Auto Scaling group based onqueue depth. Amazon SQS provides durable message storage, so orders are not lost if one processing tier scales slowly or temporarily falls behind. AWS recommends queue-based scaling when producers and consumers operate at different speeds. Monitoring CPU alone does not reflect business backlog accurately, but queue length directly represents pending work. Using two queues also lets the company scale collection and fulfillment independently, which is important because fulfillment takes longer than collection. This is the most resilient and scalable pattern for variable order traffic.

EBS gp3 volumes allow you to independently configure IOPS and throughput, up to 16,000 IOPS, regardless of the volume size, and at a lower cost compared to io1/io2 provisioned IOPS volumes. This meets the requirement for cost-effective, predictable IOPS performance for Amazon RDS for PostgreSQL.
AWS Documentation Extract:
"With gp3 volumes, you can provision performance independent of storage capacity, up to 16,000 IOPS. This allows for cost-effective scaling for applications that require high performance at a lower price point compared to io1." (Source: Amazon EBS documentation, gp3 Volumes) A: gp2 ties IOPS to volume size; 5 TiB is wasteful if only 15,000 IOPS are needed.
B: io1 works but is significantly more expensive than gp3 for most workloads.
D: Magnetic volumes do not support high IOPS.
Reference: AWS Certified Solutions Architect - Official Study Guide, EBS Storage Options.

After 180 days, the images become infrequently accessed but still must remain immediately available, which fits S3 Standard-IA better than One Zone-IA because the question requires high availability and redundancy throughout the lifecycle. AWS documents that Standard-IA is for long-lived, infrequently accessed data with millisecond access and multi-AZ resilience, while One Zone-IA stores data in a single AZ. After 360 days, the company still needs instant access, so S3 Glacier Instant Retrieval is the right archival class. AWS states that Glacier Instant Retrieval provides real-time access with lower storage cost than Standard-IA for archive data that still must be immediately retrievable. Glacier Flexible Retrieval would not meet the instant-access requirement.