Which Amazon S3 storage class is the most cost-effective for data that is infrequently accessed and can be regenerated if lost?

S3 One Zone-Infrequent Access (S3 One Zone-IA) is the most cost-effective option for infrequently accessed, regeneratable data because it stores data in a single Availability Zone, making it cheaper than multi-AZ options. Its lower durability (99.5% compared to 99.999999999% for other S3 storage classes) is acceptable given the data can be regenerated. S3 Standard is for frequently accessed data and is more expensive. S3 Intelligent-Tiering automatically moves data between access tiers but is not the absolute cheapest for this specific use case. S3 Standard-Infrequent Access (S3 Standard-IA) stores data across multiple Availability Zones, offering higher durability and thus a higher cost than S3 One Zone-IA.