Answer:
b. This would set the group ownership of file1 to root.
Explanation:
Linux allows user to have his own files and regulate the ability of other users to access them. The <em>chown</em> command allows you to use the appropriate utility to change the owner of a file or directory.
The basic command syntax is as follows:
# chown [options] <owner name: owner group name> <file or directory name>
For example, if you want to give a user <em>root</em> opportunity to use the <em>file1.txt</em> file as he wishes, you can use the following command:
# chown root file1.txt
In addition to changing the owner of a file, the group of its owners or both can be changed at the same time. Use a colon to separate the username and user group name (without the space character):
# chown user2:group2 file1.txt
As a result, the user with the name <em>user2</em> will become the owner of the <em>file1.txt</em> and its group will become <em>group2</em>.
In your case omitting username
# chown :root file1.txt
will change owner group only.