An administrator is building a web server to host an online banking application. The server should not have access to the internal network, and only ports that are used by the application should be opened. Which of the following MUST be implemented to meet the business requirements?
A. Add the server to the internal network and use IPSec to encrypt communication between the web server and other devices.
B. Use an ISA server to block access to the internal network.
C. Use VPN to block all ports that are not used by the application.
D. Use the company firewall to block all ports that are not used by the application.
