Which best describes the role of a proxy server?

[answerhappygod]

Which best describes the role of a proxy server?

A. A device that inspects Layer 2 - Layer 4 traffic running through it and denies or permits based on a set of policies.
B. An intermediary program, which acts as both a server and a client for the purpose of making requests on behalf of other clients.
C. An intermediary program that protects the resources of a private network from users on other networks.
D. A device that extracts the destination address of a packet, selects ten best path for the packet and forwards the packet the next device in the path.