On UNIX systems, passwords shall be kept:

A.
In any location on behalf of root.

B.
In a shadow password file.

C.
In the /etc/passwd file.

D.
In root.

Explanation:
When possible, on UNIX systems, passwords shall not be kept in the /etc/passwd file,
but rather in a shadow password file which can be modified only by root or a program executing on
behalf of root.