Explanation
The administrator should set PermitRootLogin to no in the /etc/ssh/sshd_config file to remove the possibility of remote administrative login via the SSH service. The PermitRootLogin directive controls whether the root user can log in using SSH. Setting it to no will deny any remote login attempts by the root user. This will harden the server and prevent unauthorized access. The administrator should also restart the sshd service after making the change. The other options are incorrect because they either do not affect the SSH service (/etc/hosts.deny or /etc/pam.d/sshd) or do not prevent remote administrative login (PubKeyAuthentication). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 13:
Managing Network Services, page 413.

After installing a new version of a package that includes a configuration file that already exists on the system, such as /etc/httpd/conf/httpd.conf, RPM will create a new file with the .rpmnew extension instead of overwriting the existing file. This allows the administrator to review the default configuration that shipped with this version and compare it with the current configuration before deciding whether to merge or replace the files. The /etc/named.conf.rpmsave file is created by RPM when a package is uninstalled and it contains a configuration file that was modified by the administrator. This allows the administrator to restore the configuration file if needed. The /etc/named.conf file is the main configuration file for the BIND name server, not the httpd web server. The /etc/bind/bind.conf file does not exist by default in Linux systems. Reference: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 19: Managing Packages and Software, page 561.