Which one of the following instigates a SYN flood attack?

A.
Generating excessive broadcast packets.

B.
Creating a high number of half-open connections.

C.
Inserting repetitive Internet Relay Chat (IRC) messages.

D.
A large number of Internet Control Message Protocol (ICMP) traces.

Explanation:
A SYN attack occurs when an attacker exploits the use of the buffer space during a Transmission Control Protocol (TCP) session initialization handshake. The attacker floods the target system’s small "in-process" queue with connection requests, but it does not respond when a target system replies to those requests. This causes the target system to time out while waiting for the proper response, which makes the system crash or become unusable.