Which of the following protocols is used when an attacker attempts to launch a man-in-the-middle...

The correct answer is B. TCP. Sequence and acknowledgment numbers are key features of the Transmission Control Protocol. In CEH networking and session hijacking concepts, TCP is a connection-oriented protocol that establishes communication using the three-way handshake: SYN, SYN/ACK, and ACK. TCP uses sequence numbers to track byte order and acknowledgment numbers to confirm receipt of data. CEH-aligned references explain that TCP session hijacking depends on tracking session traffic, predicting sequence numbers, desynchronizing the connection, and injecting packets that appear valid to the target system. TCP is therefore the protocol associated with attacks involving manipulation of sequence and acknowledgment values. ICMP is mainly used for control and diagnostic messaging, such as ping and error reporting. UDP is connectionless and does not maintain TCP-style sequence and acknowledgment numbers. IP provides addressing and routing, but it does not manage reliable sessions or acknowledgments. Because the question specifically mentions manipulating sequence and acknowledgment numbers during a MITM/session hijacking scenario, TCP is the best answer.