Which of the following is a common cyber security tool?

The choice of "all of the above" encompasses a range of essential tools used in cybersecurity, reflecting a comprehensive approach to protecting information and systems. Firewalls serve as a barrier between a trusted internal network and untrusted external networks, filtering traffic based on predetermined security rules. This helps prevent unauthorized access and data breaches.

Antivirus software is another fundamental tool that detects, prevents, and removes malicious software from devices. With the continuous evolution of malware, having antivirus software is crucial for maintaining endpoint security and ensuring that systems remain healthy and free from infection.

Two-factor authentication (2FA) adds an additional layer of security by requiring users to provide two distinct forms of identification before access is granted. This drastically reduces the risk of unauthorized access, as compromising both factors is significantly more difficult than obtaining just a password.

Since all these tools each contribute to a multi-layered security posture, relying solely on one would not provide comprehensive protection. Thus, recognizing that firewalls, antivirus software, and two-factor authentication all play vital roles in a robust cybersecurity framework justifies why selecting "all of the above" is the correct choice.