What is the purpose of a firewall in cyber security?

The correct answer is (B) To block unauthorized access to a network.

• A firewall is a network security device that monitors incoming and outgoing network traffic and decides whether to allow or block specific traffic based on a defined set of security rules. It acts as a barrier between a trusted internal network and untrusted external networks, such as the Internet.
• Firewalls can be implemented in both hardware and software forms (or a combination of both) to protect sensitive data, prevent cyber attacks, and maintain the integrity and confidentiality of organizational information systems.
• Option (A) is incorrect because allowing unrestricted access would compromise security. Option (C) is incorrect because data backups are handled by backup software or disaster recovery systems, not firewalls. Option (D) is incorrect as option (B) is the accurate description.