Answer: A

A screened subnet firewall would provide the best protection. The screening router can be a commercial router or a node with routing capabilities and the ability to allow or avoid traffic between nets or nodes based on addresses, ports, protocols, interfaces, etc. Application-level gateways are mediators between two entities that want to communicate, also known as proxy gateways. The application level (proxy) works at the application level, not only at a package level. The screening controls at package level, addresses, ports, etc. but does not see the contents of the package. A packet filtering router examines the header of every packet or data traveling between the Internet and the corporate network.   _{Your Comment}