Which of the following commands changes the ownership of file.txt to the user dan and the group staff?

The `/` character is not the correct separator for specifying user and group with `chown`; it is typically used for directory paths.

The `chown` command uses the `user:group` (or `user.group`) syntax to specify both the new user owner and the new group owner for a file, so `chown dan:staff file.txt` correctly changes the ownership.

The `-u` and `-g` options are not valid or standard ways to specify the user and group owners directly for the `chown` command.

The `-g` option is not the correct syntax for specifying the group when changing both user and group with `chown`; the correct format is `user:group`.