Which AWS service provides highly durable, effectively infinite scalable object storage for static content at the lowest cost?

Amazon S3 (Simple Storage Service) is the correct answer because it is designed for highly durable, object-based storage with virtually unlimited scalability. It's ideal for static content like images, videos, and backups, and offers various storage classes to optimize costs based on access patterns. Amazon EBS provides block-level storage for EC2 instances, not object storage for static content, and is not designed for infinite scalability as a standalone service. AWS Storage Gateway connects on-premises applications to AWS cloud storage, acting as a hybrid storage solution, not a primary object storage service. Amazon EFS offers scalable file storage for EC2 instances and on-premises resources, but it's a file system, not object storage, and typically has a higher cost profile for static content compared to S3.