a) AAA (Accounting, Authentication, Authorisation) is a framework for configuring three independent security functions consistently. Which one of the "3As" is each of these most closely related to? Why? [1] Intrusion detection system [2] Packet filter [3] Username + password b) Alice is thinking of making all users change their password every month. Why would she think this is a good idea? Bob is trying to convince her not to do this. What are his arguments against this policy? wwwwwww c) Bob wants to protect a plaintext file of user information (like Dovecot's /home/vmail/mail-pwd). Alice suggests this can be done with a special owner and particular permissions on the file and the directory where it is stored. How would this be done? How does each of these measures help restrict access?