An organization filters data packets from public networks to send to an internal private network.

A proxy gateway can filter communications between public networks and an internal private network by acting as an intermediary between external users and internal systems. It can inspect, control, and forward traffic according to security rules, thereby reducing direct exposure of internal systems. A router directs packets between networks but does not necessarily provide filtering at the application or gateway level. A switch connects devices within a network. A hub simply broadcasts traffic and offers no meaningful filtering control. Internal auditors reviewing network security should evaluate whether gateway controls filter unauthorized traffic, enforce access policies, log activity, and protect internal resources from public network exposure. Therefore, Option D is correct.