What version of SMB was once utilized by Windows servers and NAS servers but is now rarely used?

All of the answer options are communication protocols for resource sharing. The Common Internet File System (CIFS) is Microsoft's implementation of the Server Message Block protocol (SMB.) CIFS was once widely used for file sharing over a network, but it has since gone out of favor. While both CIFS and SMB support file sharing, SMB does it better and offers additional features. In Linux distributions, Samba and Network File System (NFS) provide file sharing between clients and servers. Samba will allow file sharing in mixed environments with both Windows and Linux machines. NFS will not do so.