/var/adm/messages contains this output:

Jan 28 21:23:18 mailhost in.telnetd[20911]:
[ID 808958 daemon.warning] refused connect from
ns.foo.com (access denied)

Why was this line generated?

A.
A user connecting from ns.foo.com failed to authenticate.

B.
The user daemon is not allowed to log in from ns.foo.com.

C.
A portscan was run against mailhost from ns.foo.com.

D.
The TCP Wrapper configuration does not allow telnet connections from ns.foo.com.