Which statement about the SYN flood attack is true?

Which statement about the SYN flood attack is true?

A.
The SYN flood attack is always directed from valid address.

B.
The SYN flood attack target is to deplete server memory so that legitimate request
cannot be served.

C.
The SYN flood attack is meant to completely deplete the TCB SYN-Received state
backlog.

D.
The SYN flood attack can be launched for both UDP and TCP open ports on the server.

E.
SYN-Received state backlog for TCBs is meant to protect server CPU cycles.