Which of the following are the countermeasures against a man-in-the-middle attack? Each correct answer represents a complete solution. Choose all that apply.

Which of the following are the countermeasures against a man-in-the-middle attack? Each correct answer represents a complete solution. Choose all that apply.
A . Using public key infrastructure authentication.
B . Using basic authentication.
C . Using Secret keys for authentication.
D . Using Off-channel verification.

Answer: ACD