which file is required for you to set up an environment such that every user on the other host is a trusted user that can log into this host without authentication?

In Unix, which file is required for you to set up an environment such that every user on the other
host is a trusted user that can log into this host without authentication?

A.
/etc/shadow

B.
/etc/host.equiv

C.
/etc/passwd

D.
None of the choices.

Explanation:
The /etc/hosts.equiv file is saying that every user on the other host is a trusted user and allowed to
log into this host without authentication (i.e. NO PASSWORD). The only thing that must exist for a
user to log in to this system is an /etc/passwd entry by the same login name the user is currently

using. In other words, if there is a user trying to log into this system whose login name is “bhope”,
then there must be a “bhope” listed in the /etc/passwd file.