Final Answer:
File in Linux tells the system which DNS server to use is C) /etc/resolv.conf
Step-by-step explanation:
The /etc/resolv.conf file in Linux is used to specify the DNS servers that the system should use for domain name resolution. This file typically contains information about the domain search list, nameservers, and other DNS-related configurations.
This file, located at /etc/resolv.conf, is crucial for configuring DNS (Domain Name System) settings on Linux systems.
It contains information about the DNS domain and the IP addresses of the DNS servers that the system should use to resolve domain names to IP addresses.
The file may look something like this:
nameserver 8.8.8.8
nameserver 8.8.4.4
In the example above, the IP addresses 8.8.8.8 and 8.8.4.4 are Goo gle's public DNS servers. These addresses can be replaced with the IP addresses of the DNS servers you want to use. Therefore, the correct answer is option C.