A network technician configures a firewall’s ACL to allow outgoing traffic for several popular services such as email and web browsing. However, after the firewall’s deployment, users are still unable to retrieve their emails. Which of the following would BEST resolve this issue?
A. Allow the firewall to accept inbound traffic to ports 25, 67, 179, and 3389
B. Allow the firewall to accept inbound traffic to ports 80, 110, 143, and 443
C. Set the firewall to operate in transparent mode
D. Allow the firewall to accept inbound traffic to ports 21, 53, 69, and 123