Connecting to a remote host on the same LAN using ssh public-key authentication works but forwarding X11 doesn’t. The remote host allows access to both services. Which of the following can be the reason for that behaviour?

A.
The remote user’s ssh_config file disallows X11 forwarding

B.
The remote server’s sshd_config file disallows X11 forwarding

C.
A different public key has to be used for X11

D.
X11 cannot be forwarded if public-key authentication was used

E.
X11 though SSH needs a special X11 server application installed