What device monitors and controls incoming and outgoing traffic in a network?

The correct choice is a firewall, as it is specifically designed to monitor and control incoming and outgoing traffic within a network. Firewalls establish a barrier between trusted internal networks and untrusted external networks, such as the Internet. They enforce security policies by allowing or blocking data packets based on predetermined rules. This capability is crucial in protecting networks from unauthorized access, malware, and various cyber threats.

In contrast, while routers do manage traffic between different networks and may include some basic security features, their primary function is to direct data packets to their proper destinations. Switches connect devices within a single network and facilitate communication by forwarding data to specific devices rather than monitoring traffic for security purposes. Hubs, being basic networking devices, broadcast data to all connected devices without any filtering or control of traffic, making them less efficient and secure compared to firewalls.