A data engineering team is developing a new application that requires intermittent access to a relational database. The application’s usage is expected to have unpredictable peaks and valleys. The team stores the application data in Amazon S3 and needs an on-demand relational database solution that can automatically scale to match the application’s workload and minimize operational management and cost. Which AWS service should the data engineering team use to meet the application’s database requirements with auto-scaling capabilities and direct integration with Amazon S3?