Which of the following can best protect a computer when an infected file has been...

Anti-malwaresoftware is specifically designed to detect, quarantine, and remove malicious software from a system. It is the most appropriate tool for protecting a computer after a suspicious or infected file is downloaded.

“Anti-malware software scans downloaded files and running processes to identify and remove malicious software, providing real-time protection against viruses, trojans, and spyware.” — CompTIA ITF+ Study Guide

Other options:

B. Firewall – Prevents unauthorized access but doesn’t clean infections

C. Patching – Prevents exploitation of known vulnerabilities, not infection removal

D. Permissions – Limit access but do not remove malware

Correct answer: A