On a new Linux system, the root user is being asked to provide the root user password before being able to use the su command. What line in the /etc/ pam.d/su file will allow root to use su without supplying passwords?
A. auth required pam_norootpw.so
B. auth sufficient pam_norootpw.so
C. auth required pam_rootok.so
D. auth sufficient pam_rootok.so