The correct answers are: B. dns D. files Explanation: The /etc/nsswitch.conf file controls the order in which different sources are consulted for various types of information, including hostnames. Here's how the keywords you mentioned are used: dns: Specifies that the Domain Name System (DNS) should be used for hostname resolution. files: Specifies that the /etc/hosts file (or its equivalent) should be checked for hostname mappings. The other options are not valid sources for host name lookups in /etc/nsswitch.conf: resolv: While related to DNS resolution, it's not a keyword used directly in nsswitch.conf. remote: This is not a standard keyword in nsswitch.conf. hosts: While the /etc/hosts file is used for hostname lookups, the keyword is files in nsswitch.conf.