The correct answer is A, Security. AWS Config is a service that enables you to assess, audit, and evaluate the configurations of your AWS resources over time. It records changes to resource configurations and provides a detailed view of how the configurations are aligned with best practices and desired configurations. By using AWS Config, you can track and maintain traceability of changes to your resources, helping to enforce security controls, detect unauthorized changes, and ensure compliance with security requirements. This aligns with the Security pillar of the AWS Well-Architected Framework, which focuses on protecting information, systems, and assets while maintaining data confidentiality, integrity, and availability.