What text file is used to configure, among other things, the source databases used for resolving host names, domain names, logins, and passwords?

What text file is used to configure, among other things, the source databases used for resolving host names, domain names, logins, and passwords?

A.
/etc/shadow

B.
/etc/resolv.conf

C.
/etc/exports

D.
/etc/services

E.
/etc/nsswitch.conf