What should the permission settings be for /etc/passwd …

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