The second paragraph in the slide notes state:
VMFS provides an interface to storage resources so that several storage protocols (Fibre Channel, Fibre Channel over Ethernet, iSCSI and NAS) can be used to access datastores on which virtual machines can reside.Correct:
VMFS does not provide an interface to the NAS protocol, it is instead the NFS datastore that provides it.Info:
VMFS datastores support SCSI compliant block access storage (Fibre Channel, Fibre Channel over Ethernet and iSCSI), whilst NFS datastores support non-SCSI compliant file access storage (NAS).Source:
vSphere 5.1 Documentation Center.