Linux Extended Attributes include attribute classes. Which of the following are included in the defined attribute classes? (Select THREE correct answers)

`default` is not a defined attribute class or namespace for extended attributes in Linux.

The `system` attribute class is used by the kernel for internal purposes, such as storing POSIX ACLs and security attributes, and typically requires root privileges for access.

`owner` is not a defined attribute class or namespace for extended attributes in Linux; permissions are handled by standard file permissions and ACLs.

The `trusted` attribute class stores attributes that can only be read or modified by processes with specific elevated capabilities (e.g., `CAP_SYS_ADMIN`), making them suitable for sensitive system information.

The `user` attribute class allows regular users to store arbitrary metadata on files, subject to file permissions, without requiring special privileges beyond those needed to write to the file itself.