What is the primary function of a firewall in computer networks?

The primary function of a firewall in computer networks is to protect a network by controlling traffic based on security rules. Firewalls act as a barrier between a trusted internal network and untrusted external networks, such as the internet. They monitor and filter incoming and outgoing network traffic based on predetermined security rules, allowing only authorized communications. This capability helps to prevent unauthorized access, data breaches, and cyber threats, thus ensuring the security and integrity of the network.

While enhancing internet speed, securely storing data, and improving user access to applications might be important aspects of network management and performance, they are not the primary roles of a firewall. The focus of a firewall is strictly on security, making option C the correct choice for this question.