A company wants to migrate a legacy workload from its on-premises data center to AWS without making any changes to the workload. Which migration strategy best fits this requirement?

Rehost, also known as "lift and shift," is the best strategy because it involves migrating applications as-is from on-premises to AWS without making significant changes to the application architecture. This directly addresses the requirement of migrating a legacy workload without any modifications. Repurchase involves replacing an existing application with a new, cloud-native version or a SaaS solution, which would require changes and is not suitable for a "no changes" requirement. Replatform involves making some cloud-specific optimizations to the application to take advantage of cloud features, but without changing the core architecture, which still implies some changes. Refactor involves re-architecting the application to be fully cloud-native, which is a significant change and the opposite of the stated requirement.