What should the permission settings be for /etc/passwd and /etc/shadow?

A.
/etc/passwd: -rw-r–r– /etc/shadow: -r——-

B.
/etc/passwd: -r——- /etc/shadow: -rw-r–r–

C.
/etc/passwd: -rw-r-r- /etc/shadow: -rw-r–r–

D.
/etc/passwd: -r——- /etc/shadow: -r——-

Explanation/Reference:
shadow is a file which contains the password information for the systems accounts and optional aging information. This file must not be readable by regular users if password security is to be maintained.
The passwd file should be world-readable.