What protocol uses UDP and operates on port 69?

The correct choice identifies the Trivial File Transfer Protocol (TFTP), which utilizes User Datagram Protocol (UDP) for data transmission and operates specifically on port 69. TFTP is a simplified version of FTP and is designed for transferring files with minimal overhead. Unlike FTP, which requires a connection-oriented protocol like TCP, TFTP is connectionless, making it more suitable for scenarios where simplicity and speed are prioritized over reliability and features like authentication.

TFTP is commonly used for tasks such as booting devices over a network and transferring configuration files due to its lightweight nature. The use of UDP allows for faster transmissions as it does not require the extensive handshaking that TCP does; however, it does sacrifice reliability, as there is no built-in error recovery mechanism in TFTP.

In context with the other protocols listed, HTTP operates over port 80 and is designed for transferring web pages; FTP typically runs on ports 20 and 21 and is used for more complex file transfers with a range of features; SNTP (Simple Network Time Protocol) operates on a different port, usually 123, and is used for synchronizing clocks over the network. Thus, the defining characteristics of TFTP align perfectly with the details of the question.