Which VMware functionality allows migration of VMs between ESXi hosts with different CPU architectures?

Enhanced vMotion Compatibility (EVC) is the correct choice because it provides a mechanism for migrating virtual machines between ESXi hosts that have different CPU architectures. EVC ensures that all participating hosts present a consistent CPU feature set to the virtual machines, allowing for seamless migrations. This is particularly important in environments where hosts may have different hardware, as it mitigates compatibility issues related to CPU instructions.

By enabling EVC, administrators can cluster hosts with varying CPUs and still utilize vMotion without encountering errors related to CPU feature compatibility. EVC works by masking certain CPU features to the virtual machines, allowing them to operate on a broader range of hardware, which is essential for maintaining high availability and flexibility in a virtualized environment.

The other functionalities listed do not address the migration of VMs between hosts with differing CPU architectures. For instance, vSphere Storage DRS manages the placement and load balancing of virtual machine disks across datastores, while vSphere HA provides automated failover for virtual machines in case of host failure. VMware Fault Tolerance allows continuous availability for virtual machines but does not specifically cater to migrations between hosts with different CPU models.