In a SYN Flood DoS attack, the $\_\_\_\_\_\_$ packet or message is never returned from the client to the victim computer. This causes the $\_\_\_\_\_$ table to fill up$,$ preventing any other legitimate user from making the connection to the victim, and causing the DoS attack.

Question $6$ options:

a$)$

SYN$-$ACK; connection

b$)$

ACK; connection

c$)$

SYN; user

d$)$

ACK; ICMP