A company is building an application on AWS that connects to an Amazon RDS database. The company wants to manage application configuration and securely store and retrieve database and other service credentials. Which solution meets these requirements with the LEAST administrative overhead?

The correct answer leverages purpose-built AWS services for configuration and secrets management, offering the least administrative overhead. AWS AppConfig is designed for managing application configurations, allowing for controlled deployments and rollbacks. AWS Secrets Manager is specifically for securely storing, managing, and retrieving database credentials, API keys, and other secrets, including automatic rotation. Using AWS Lambda for configuration management is not its primary purpose and would require significant custom development and maintenance. AWS Systems Manager Parameter Store can store credentials but lacks the advanced features of Secrets Manager like automatic rotation for database credentials. Storing encrypted configuration and credentials in S3 is possible but requires custom code for encryption/decryption, retrieval, and rotation, increasing administrative overhead. Storing credentials directly in Amazon RDS is not a secure practice and is not supported for general application credentials.