Final answer:
UDP is preferred for live video or audio streaming due to its speed and efficiency, which are paramount in maintaining a seamless experience.
Step-by-step explanation:
The User Datagram Protocol (UDP) is preferred over Transmission Control Protocol (TCP) for scenarios where speed and efficiency are more critical than reliability. One such scenario is live video or audio streaming, where it is crucial to maintain a constant flow of data without the overhead of ensuring every single packet is received and in the correct order. This is in contrast to applications requiring high reliability and data integrity, like email, file downloads, and secure transactions, where TCP is generally preferred.