When the useradd command is used to add a user to a Linux system, which two files are used that contain configuration information such as default location for email, password expiration information, minimum password length, and so on$?$

a$./$etc$/$useradd$.$conf

b$./$etc$/$login$.$defs

c$./$etc$/$default$/$useradd

d$./$etc$/$default$/$logins$.$conf