What is a DNS server?

A DNS server, or Domain Name System server, is primarily responsible for translating human-readable domain names into machine-understandable IP addresses. This process is crucial because while users usually remember domain names like www.example.com, the Internet relies on IP addresses to find and connect to devices. When you enter a domain name in your web browser, your computer queries a DNS server to retrieve the corresponding IP address, enabling your device to connect to the desired website.

This function makes the correct option the most relevant, as it directly describes the primary role of a DNS server within the network infrastructure. The other options reference different types of servers that serve unrelated purposes: email services involve transmitting messages between users, website hosting pertains to storing and delivering web content to users, and file backup servers are focused on data storage for retrieval and recovery. Hence, these do not align with the function of a DNS server.