What does the Domain Name System (DNS) primarily do?

The Domain Name System (DNS) primarily serves the critical function of converting IP addresses into human-readable domain names. This process is essential because while computers communicate via IP addresses, these numerical identifiers are not easily memorable for users. By translating user-friendly domain names, like www.example.com, into the corresponding IP addresses, DNS enables users to access websites and internet resources without needing to remember complicated sequences of numbers.

The other options, while related to various internet functions, do not accurately describe the primary role of DNS. Facilitating secure transactions online involves protocols such as HTTPS and SSL, which are unrelated to DNS's primary task. Managing email communications is typically handled by protocols like SMTP, IMAP, or POP, and does not fall under the umbrella of DNS functions. Hosting websites on servers refers to the storage of website data, which is distinct from the DNS role of resolving names to addresses. Thus, the correct answer emphasizes DNS's fundamental purpose in making the internet accessible and navigable for users.