A data engineer must perform a one-time analysis that joins data stored in Amazon DynamoDB, Amazon RDS, Amazon Redshift, and Amazon S3. Which approach is the MOST cost-effective for joining these data sources for a single analysis job?

Amazon Athena Federated Query is the most cost-effective solution for a one-time analysis across diverse data sources like DynamoDB, RDS, Redshift, and S3. It allows Athena to query data directly in place without moving it, minimizing data transfer and storage costs. Athena is serverless, so you only pay for the queries you run. Using an Amazon EMR provisioned cluster would incur costs for the cluster's uptime, even for a single analysis, making it less cost-effective. Copying all data to S3 would involve data transfer costs and potentially duplicate storage costs, which is inefficient for a one-time job. While Redshift Spectrum can query S3 data, it cannot directly query DynamoDB or RDS without additional steps, and running queries through Redshift would incur Redshift cluster costs.