The least operational overhead approach is to use managed Amazon Bedrock model evaluation workflows with datasets stored in Amazon S3, and then publish results into Amazon CloudWatch for dashboards. That is exactly what options B and C combine.

Step B correctly places standardized evaluation inputs in Amazon S3 and focuses on granting the evaluation workflow the right permissions to read those datasets. In practice, the key requirement is controlled access to the S3 objects used as evaluation datasets. Establishing IAM permissions and private access patterns (such as using VPC connectivity patterns where applicable to the organization’s networking posture) is aligned with enterprise requirements and avoids building custom storage or data distribution systems for evaluators.

Step C then operationalizes the evaluation lifecycle with minimal infrastructure: a scheduled AWS Lambda function starts evaluation jobs using the S3 dataset location, and a second Lambda function checks job status and pushes results and operational signals to CloudWatch. This meets the platform requirement to surface accuracy metrics in dashboards because CloudWatch metrics/logs can be visualized in dashboards and queried through CloudWatch Logs Insights. It also supports continuous, standardized comparisons across models without requiring developers to run ad-hoc experiments.

The alternatives introduce more operational burden. D and E rely on Amazon SageMaker-based tooling, notebook jobs, and open source evaluation frameworks, which require more environment management, dependency control, scaling considerations, and maintenance over time. A includes CORS, which is primarily a browser-access concern and does not address how Bedrock-managed evaluation jobs securely access S3 in the typical service-to-service pattern.

Therefore, B + C achieves standardized model evaluation, automated scheduling, and dashboard-ready observability with the smallest operations footprint.