How can these requirements be met?

Explanations:

While Amazon S3 Glacier Vault allows for long-term storage and expedited retrieval, it incurs costs for retrieval and is not designed for immediate access without additional fees. It is primarily intended for infrequent access to archival data.

AWS Storage Gateway with cached volumes retains frequently accessed data locally, minimizing bandwidth costs. It allows immediate retrieval of data from the local cache while storing the rest in Amazon S3, thus meeting the requirement for immediate access without additional costs.

Using stored volumes would mean that data is primarily kept locally and only asynchronously backed up to S3. This does not address immediate retrieval needs for data stored in S3 and does not optimize for bandwidth costs as effectively as cached volumes.

While AWS Direct Connect provides a dedicated network connection to AWS, it does not solve the immediate retrieval requirement on its own. Using stored volumes for local storage would still result in asynchronous backups to S3, which does not ensure immediate retrieval at no additional cost.