How is file ownership determined in Linux?

File ownership in Linux is determined by the user ID (UID) and the group ID (GID). Every file in a Linux file system is associated with a specific user and group. The UID represents the owner of the file, while the GID denotes the group that has permissions to access or modify the file. This structure allows for precise control over file permissions and ownership, enabling multiple users and groups to interact with files in a secure environment.

The other choices relate to file attributes but do not define ownership. Filenames are simply labels for files and do not convey any ownership information. File size indicates how much data a file contains but has nothing to do with who owns it. The last modified date reflects when a file was last edited, but again, it does not influence or indicate the ownership status of the file. Thus, the relationship between UID/GID and file ownership is fundamental to Linux's permission and security model.