题目：How do TCP and UDP differ in the way that they establish a connection between two endpoints?
A、 TCP uses synchronization packets, and UDP uses acknowledgment packets.
B、 UDP uses SYN, SYN ACK and FIN bits in the frame header while TCP uses SYN, SYN ACK and ACK bits
C、 UDP provides reliable message transfer and TCP is a connectionless protocol
D、 TCP uses the three-way handshake and UDP does not guarantee message delivery
