Which best describes the mechanism of a TCP SYN flood?

A.
The attackers keeps open many connections with slow data transmission so that other clients cannot start new connections.

B.
The attackers sends a packets designed to sync with the FortiGate

C.
The attacker sends a specially crafted malformed packet, intended to crash the target by exploiting its parser.

D.
The attacker starts many connections, but never acknowledges to fully form them.