Which command will verify the syntax of the hosts.allow and host.deny files?

A.
tcpdchk

B.
tcpdmatch

C.
verify –tcp

D.
ipswitch

Explanation:
From the man pages:
tcpdchk examines your tcp wrapper configuration and reports all potential and real problems it can find. The program examines the tcpd access control files (by default, these are /etc/hosts.allow and /etc/hosts.deny), and compares the entries in these files against entries in the inetd network configuration file.
tcpdchk reports problems such as non-existent pathnames; services that appear in tcpd access control rules, but are not controlled by tcpd; services that should not be wrapped; non-existent host names or non-internet address forms; occurrences of host aliases instead of official host names; hosts with a name/address conflict; inappropriate use of wildcard patterns; inappropriate use of NIS netgroups or references to non-existent NIS netgroups; references to non-existent options; invalid arguments to options; and so on.