Which solution is the MOST scalable and cost-effective way to meet these requirements?

Explanations:

This option involves using Amazon Kinesis for report delivery and Amazon EMR for analysis. While EMR is powerful for large-scale data processing, it is generally more complex and costlier compared to other options like Athena, especially for monthly queries. Kinesis also adds unnecessary complexity for simply handling Cost and Usage Reports.

This option delivers Cost and Usage Reports to Amazon S3 and uses Amazon Athena for analysis. Athena allows for serverless SQL queries directly on data stored in S3, making it highly scalable and cost-effective for monthly reporting needs. There are no additional infrastructure costs involved, and it simplifies data access.

Enabling Cost and Usage Reports for member accounts and delivering them to Amazon S3 with analysis through Amazon Redshift may not be the best choice. Redshift requires provisioning and managing a data warehouse, which can be costly and complex for a monthly analysis. It is more suited for continuous and large-scale data analysis rather than infrequent reporting.

This option uses Amazon Kinesis for delivery and Amazon QuickSight for analysis. Similar to option A, using Kinesis adds complexity without necessity for this task. QuickSight is a BI tool for visualization but relies on processed data, which makes it less efficient for querying raw Cost and Usage Reports directly compared to Athena.