Explanation
A file server is a computer that provides a location for shared disk access, i.e. storage of computer files (such as text, image, sound, video) that can be accessed by other computers on the same network2. A general purpose file server is a file server that serves shares such as team shares, user home folders, work folders and software development shares3.
According to 4, a purpose-built NAS solution is a storage system that simplifies data management with easy NAS file sharing. A NAS solution provides shared access to files over a network using protocols such as NFS and SMB/CIFS5.
Based on these definitions4, a benefit of using a purpose-built NAS solution vs general purpose file servers is A. provides more efficient file sharing across Windows and Linux users6. This is because a purpose-built NAS solution supports both NFS and SMB/CIFS protocols that enable file sharing across different operating systems5.