What is the difference between 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)

TCP vs UDP differ in how they handle data transport. TCP is connection-oriented and reliable: it sets up a connection before sending data, uses acknowledgments and retransmissions to ensure every byte is received, and preserves the order of data. UDP is connectionless and faster but less reliable: it sends datagrams without a prior setup and without guarantees of delivery or order, which reduces overhead and latency.

This is why the best answer says TCP is connection-oriented and reliable, while UDP is connectionless and faster but less reliable. The other statements miss key aspects: TCP isn’t connectionless, both protocols aren’t both connection-oriented, and while TCP does guarantee order and delivery, that description doesn’t capture the full contrast in connection style and overhead.