An application uses a Lambda function to write data to an Amazon RDS for PostgreSQL database. A developer created a database user for the application and wants to manage the user credentials in AWS Secrets Manager, rotating the password regularly. The rotation process must ensure high availability and no application downtime during secret rotation. What should the developer configure?

The correct choice is to configure automatic rotation using the alternating-users rotation strategy. This strategy is designed for high availability and no application downtime. It creates a temporary user with the same permissions as the primary user, rotates the primary user's password, and then deletes the temporary user. This ensures that the application can continue to use the old credentials while the new ones are being set up, preventing any interruption. The single-user rotation strategy directly rotates the password of the single database user, which can cause downtime if the application tries to connect with the old password during the rotation process. Managed rotation is a general term; the key is the specific strategy (single-user vs. alternating-users) and the automatic nature of the rotation.