Final answer:
DNS stands for Domain Name System and is a distributed hierarchical naming system. It matches domain names to their IP addresses and arranges them in a branching structure for efficient query resolution and to support scalability.
Step-by-step explanation:
DNS stands for Domain Name System, and it is option 1) The distributed hierarchical naming system. DNS is a critical component of the Internet infrastructure that provides a way to match domain names (e.g., www.example.com) to their associated IP addresses (e.g., 192.0.2.1). Without DNS, we would have to remember the IP addresses of all the servers we want to visit, which is not feasible given that there are million active domain names as of now.
Describing DNS as a distributed hierarchical naming system highlights that DNS is structured in multiple, branching levels, starting from the '.' or root level, moving to top-level domains (TLDs), then to second-level domains, and so forth. This structure allows for efficient query resolution and avoids the need to have a single database that contains every domain name and its corresponding IP address, therefore keeping DNS scalable and robust.