A company plans to migrate a PostgreSQL database to AWS but uses it infrequently. Which option provides the least operational management?

Amazon Aurora Serverless is the correct choice because it automatically starts up, shuts down, and scales capacity based on application demand, requiring the least operational management. This is ideal for infrequently used databases as it only consumes and charges for resources when active. Amazon Aurora PostgreSQL-Compatible Edition and Amazon RDS for PostgreSQL are managed database services, reducing operational overhead compared to EC2, but they still require some capacity planning and management, and they run continuously. PostgreSQL on Amazon EC2 offers the most control but requires the most operational management, including patching, backups, and scaling, making it unsuitable for the "least operational management" requirement.