Amazon Glacier is best suited for which of the following requirements?

Amazon Glacier is specifically designed to provide a low-cost storage solution primarily for long-term backup and archival purposes. It caters to use cases where data is infrequently accessed but still needs to be stored securely for an extended period. This service allows organizations to store vast amounts of data that they may not need to access immediately but must retain for compliance or other regulatory reasons.

The architectural choices and cost structure of Amazon Glacier align perfectly with archiving needs. It offers an incredibly low cost per gigabyte, making it a favorable option for businesses looking to minimize storage expenses while maintaining data accessibility for future use, albeit with slower retrieval times compared to more access-focused storage services.

On the other hand, other choices hinge on requirements for immediacy or temporary use, which do not align with the characteristics and intended use cases of Amazon Glacier. For example, high-frequency, quick access data storage would be better suited for services like Amazon S3, while real-time data processing requires solutions that allow for rapid accessibility, such as Amazon DynamoDB or Amazon RDS. Temporary storage needs also do not fit Glacier's purpose, as they usually involve quick deletions or transformations that don’t necessitate long-term retention.