Which AWS service or resource will meet these requirements with the LEAST management overhead?

Explanations:

Running PostgreSQL on Amazon EC2 requires significant management overhead, including operating system maintenance, database patching, backups, scaling, and monitoring. This option is not ideal for a company that does not frequently use the database.

Amazon RDS for PostgreSQL automates some management tasks such as backups and patching, but it still requires ongoing management, especially regarding scaling and cost management, which may not be suitable for infrequent usage.

Amazon Aurora PostgreSQL-Compatible Edition offers performance and scalability improvements over standard PostgreSQL but still requires regular management, including backups, scaling, and patching. This may be more than what is needed for infrequent usage.

Amazon Aurora Serverless provides an on-demand, auto-scaling database service that automatically adjusts capacity based on application needs. It has the least management overhead as it eliminates the need for database provisioning, scaling, and maintenance, making it ideal for a company that infrequently uses the database.