Which statement correctly contrasts TCP and UDP?

• A. TCP is connectionless and faster than UDP.
• B. TCP is connection-oriented and reliable; UDP is connectionless and faster but less reliable.
• C. TCP and UDP are both connection-oriented.
• D. TCP guarantees order and delivery; UDP does not.

Answer: (B)

Understanding how TCP and UDP differ in setup and guarantees helps you pick the right transport for a task. TCP is connection-oriented: it establishes a session before data flows, and it keeps state for the connection. It is reliable because it uses acknowledgments and retransmissions to ensure every byte arrives correctly and in order. It also implements flow and congestion control to manage the rate of data. All that overhead makes TCP slower but guarantees data integrity and sequence. UDP is connectionless: there’s no handshake or persistent session, and datagrams are sent without built-in delivery guarantees. It doesn’t promise order, nor does it ensure delivery, so some packets can be lost or arrive out of order. Because UDP carries less overhead, it’s faster and lighter, which is desirable for real-time or loss-tolerant applications. That’s why the correct contrast is that TCP is connection-oriented and reliable, while UDP is connectionless and faster but less reliable.