Which of the following descriptions about HTTP Flood defense is incorrect?

Which of the following descriptions about HTTP Flood defense is incorrect?
A . If the free proxy used during the attack supports the redirection function, the basic mode defense will be ineffective.
B . The source authentication defense method is to defend against HTTP
C . Defense based on enhanced mode can determine whether the TTP access is initiated by a real user by asking the user to enter a verification code.
D . Defense based on basic mode cannot effectively prevent access from non-browser clients

Answer: D