The correct answer is: Country Code Top-level Domains (ccTLD)
A country code top-level domain (ccTLD) is a top-level domain (TLD) in the Internet Domain Name System (DNS) that is used to identify websites or other Internet resources that are associated with a particular country, sovereign state, dependent territory, or other geographic region.
The .uk domain is the country code top-level domain for the United Kingdom. It was introduced in 1985 and is one of the oldest ccTLDs in the world. The .uk domain is managed by Nominet UK, a non-profit organization that is responsible for the registration of domain names in the United Kingdom.
Generic top-level domains (gTLDs) are top-level domains that are not associated with a particular country or region. They are used to identify websites or other Internet resources that are not associated with a specific geographic location. Some examples of gTLDs include .com, .net, and .org.
Sponsored top-level domains (sTLDs) are top-level domains that are sponsored by a specific organization or group. They are used to identify websites or other Internet resources that are associated with a particular industry or sector. Some examples of sTLDs include .aero, .biz, and .coop.
Infrastructure top-level domains (iTLDs) are top-level domains that are used to identify Internet infrastructure resources. They are not associated with a particular country or region, and they are not used to identify websites or other Internet resources. Some examples of iTLDs include .arpa, .int, and .mil.