While checking your security, you discover that you can connect to one of the machines on the network via port 23. What should you do to the network service on
this machine?

A.
Deactivate it, you don’t need a SMTP server there.

B.
Deactivate it, you should not use TELNET.

C.
Leave active, SSH is safe.

D.
Deactivate it, you don’t need a FTP server there.