The most appropriate security method used to protect your files and the state of your computer among the options provided is Data Backup.
Data backup is essential for preserving important files and ensuring that you can restore your system to its previous state in case of data loss due to hardware failure, malware, or other issues. While antivirus software protects against malware, operating system patches update vulnerabilities, software updates can enhance performance or features, and backing up your data specifically allows recovery after data loss incidents.