An administrator is having a problem configuring Storage I/O Control on a Datastore. Which two conditions could explain the issue? (Choose two.)

SIOC was introduced in vSphere 4.1 and is not available on ESXi 4.0 hosts; if any host accessing the datastore runs ESXi 4.0, vCenter cannot enable SIOC because all participating hosts must support the feature.

SIOC requires the vSphere Enterprise Plus license on every ESXi host that accesses the datastore; a host with an insufficient license level prevents SIOC from being activated on that datastore.

vCenter Server 5.0 fully supports configuring and managing SIOC, so the vCenter version is not a blocking condition here.

SIOC configuration is controlled by host-level licensing, not by the vCenter Server license tier; a Standard vCenter license does not prevent SIOC from being enabled.