Which of the following would MOST likely prevent malware sent as a compromised file via email from infecting a person's computer?

To prevent malware sent as a compromised file via email from infecting a person's computer, the most effective option would be to utilize antivirus software. This type of software is specifically designed to detect, quarantine, and remove malicious software before it can execute and cause harm. Antivirus programs work by scanning files for known malware signatures, monitoring behaviors of programs for suspicious activities, and providing real-time protection against attacks.

While patching is critical in keeping software updated to fix vulnerabilities that could be exploited, it does not directly address the problem of malware arriving via email attachments. Firewalls primarily act as barriers to control incoming and outgoing network traffic, which may help prevent some types of attacks but are not specifically designed to filter email attachments or detect embedded malware within files. A VPN (Virtual Private Network) primarily secures internet connections and protects privacy online, but it does not offer protection against malware contained within files received through email.

Thus, antivirus software is the most effective choice in this context, as it provides targeted protection against the specific threat posed by compromised file attachments in emails.