Which solution will meet these requirements?

Explanations:

An Amazon S3 File Gateway provides an interface to access S3 storage but does not provide low-latency access to frequently used data directly from on-premises systems. It is designed for file-based access, not for block storage, which would be needed to replace iSCSI servers.

While Amazon Elastic Block Store (EBS) is a suitable option for block storage, it is designed for use with Amazon EC2 instances. It would not directly replace on-premises iSCSI servers without additional infrastructure changes and does not provide a direct low-latency access solution to on-premises systems.

An AWS Storage Gateway volume gateway configured with stored volumes stores the entire data set on-premises. This option does not effectively reduce the dependency on on-premises servers and does not provide caching benefits for low-latency access to frequently used data.

Deploying an AWS Storage Gateway volume gateway configured with cached volumes allows frequently accessed data to be stored in Amazon S3, while the most active data is cached locally. This setup provides low-latency access to frequently used data and minimizes the reliance on on-premises infrastructure.