What is the main difference between TCP and UDP?

The correct choice highlights that TCP (Transmission Control Protocol) is connection-oriented and reliable, while UDP (User Datagram Protocol) is connectionless and typically faster in terms of data transmission.

TCP establishes a connection before data can be sent, ensuring that packets are delivered in order and without errors. This is achieved through mechanisms like error checking, retransmission of lost packets, and flow control. As a result, applications that require reliable communication, such as file transfers or email, often use TCP.

On the other hand, UDP does not set up a connection before sending data. It simply sends packets (datagrams) without guaranteeing their delivery, order, or integrity. This makes UDP much faster than TCP, as there is no need for the overhead of establishing a connection or checking for errors. It is often preferred for applications like video streaming or online gaming where speed is more critical than reliability.

The other options reflect misunderstandings about the fundamental characteristics of these two protocols. For example, TCP being connectionless or UDP being slower contradicts the established definitions of both protocols. Additionally, while UDP does prioritize speed, it does not inherently prioritize quality; rather, it sacrifices some reliability to achieve this speed.