What is the purpose of an explicit "deny any" statement at the end of an ACL？（）

• A、none，since it is implicit
• B、to enable Cisco IOS IPS to work properly；however，it is the deny all traffic entry that is actually required
• C、to enable Cisco IOS Firewall to work properly；however，it is the deny all traffic entry that is actually required
• D、to allow the log option to be used to log any matches
• E、to prevent sync flood attacks
• F、to prevent half-opened TCP connections