Which statement about TCP and UDP is true?

• A. TCP is reliable and connection-oriented; UDP is unreliable and connectionless but faster; use TCP for web/email, UDP for streaming or real-time apps.
• B. UDP is reliable and ensures packet ordering in all cases.
• C. TCP is faster for streaming than UDP.
• D. UDP provides reliable in-order delivery.

Answer: (A)

The statement tests how TCP and UDP differ in reliability, connection state, and typical use. TCP provides reliable data transfer and is connection-oriented: a connection is established, data is delivered reliably with acknowledgments, and packets are delivered in order, with retransmissions if needed. This extra work adds overhead and can introduce some latency, but it ensures you get everything correctly, which is essential for web pages and email where missing data would be problematic.

UDP, on the other hand, is connectionless and does not guarantee delivery or ordering. It has much lower overhead, so it can be faster and more suitable for real-time or streaming applications where a few lost packets are acceptable and latency matters more than perfect accuracy.

So the statement is true because it correctly captures these trade-offs: TCP is reliable and connection-oriented; UDP is unreliable and connectionless but faster, making TCP a good choice for web/email and UDP a better fit for streaming or real-time apps. The other options misstate UDP’s reliability or TCP’s speed for streaming.