View the Exhibit. 
A normal user bob logs in from server200 to server1 through telnet and runs the xclock command
but fails with an error message as shown in the Exhibit.
What could be the possible reason for the error?
A.
This is because gdm is not started on the machine.
B.
This is because of the temporary failure in name resolution.
C.
This is because the default X access controls do not permit remote connections.
D.
This is because the graphical display manager is not configured to allow TCP connections.
Explanation: