Final answer:
DNS stands for Domain Name System and is best described as the distributed hierarchical naming system, Option A. It translates domain names into IP addresses and has a hierarchical structure with a global network of servers to efficiently manage internet traffic.
Step-by-step explanation:
The correct answer to your question about DNS is A. The distributed hierarchical naming system. DNS stands for Domain Name System, which is an integral part of the internet's infrastructure. Its main function is to translate user-friendly domain names like 'example.com' into IP (Internet Protocol) addresses that computers use to identify each other on the network.
DNS is indeed distributed and hierarchical. The hierarchy is evident in the structure of domain names, with top-level domains at the highest level (like .com, .org, .net), and subdomains for each domain. The distribution comes from the global network of DNS servers that help route the information correctly and efficiently across the internet.
In contrast, a vertical naming system would imply that the names follow a single path or a strict linear order, which is not how DNS is structured.
A horizontal naming system would suggest a flat structure without a hierarchy, which is also inaccurate for DNS. Lastly, The client-server system is a more general concept referring to the model of network architecture, which includes DNS but isn't specific enough to describe its naming system.