in a NAS environment, which file system provides a public or open variation of the...

In a NAS environment, the Common Internet File System (CIFS) provides a public or open variation of the Server Message Block (SMB) protocol. CIFS is designed to allow file sharing over a network and is built on the TCP/IP protocol. It enables users to access files on remote systems as if they were on their local machines, supporting file sharing, printing, and various network services.

References:

Dell Information Storage and Management V5 course materials, section on NAS protocols

Dell EMC documentation on CIFS