Which One Of The Following Uses UDP As The Transport Protocol: A)HTTP B)Telnet C)DNS D)SMTP?

UDP is a simple connectionless protocol that provides no real features but is very fast. It is ideally suited for small, quick exchanges of information, and can be faster than TCP because there is no need to establish a connection and therefore provide error control, unlike with HTTP, SMTP and Telnet protocols.

The biggest and basic use of DNS is to elaborate hostnames to IP addresses. It is in very easy terms like a phone diary. For example, if you desire to know the internet address of en.wikipedia.org, DNS can be used to explain you it's 66.230.200.100. DNS also has many useful uses.

Pre-eminently, the DNS does it possible to give Internet destinations to the human company or specific they represent,the one and only way of the physical routing hierarchy showed by the numerical IP address. Because of this, hyperlinks and Internet address information can exist the similar, whatever the frequently used IP routing arrangements may be, and can give a human-readable way(such as "wikipedia.org") which is rather simpler to remember than an IP address (such as 66.230.200.100). Human  take benefit of this when they recite knowledgeable URLs and e-mail addresses without take into notice how the machine will really locate them.

The DNS also spread the responsibility for giving domain names and measuring them to IP networks by giving control an authoritative server for each domain to save track of its own updates, preventing the need for a central registrar to be regularly consulted and updated.

C) DNS
DNS uses UDP as the transport protocol