You have a privately addressed email server behind your Firebox. If you want to make sure that all traffic from this server to the Internet appears to come from the public IP address 203.0.113.25, regardless of policies, which from of NAT would you use? (Select one.)
To ensure that all traffic from the email server to the Internet appears to come from the public IP address 203.0.113.25, regardless of specific policies, you should create a global dynamic NAT rule for traffic from the email server and set the source IP address to 203.0.113.25. This approach ensures that the NAT is applied universally to all outbound traffic from the email server, not just to traffic handled by specific policies.
Both A and B are applicable, however the question specifically states "regardless of policies", thus B is correct.
Nah, it says "make sure that all traffic". SMTP Policy is not "all" traffic ;-)
More importantly "regardless of policies", as mentioned by CD990