Final answer:
The command used to check and fix corrupted system files in Windows 10/11 is the System File Checker (SFC) utility, which is executed using 'sfc /scannow' in an elevated command prompt.
Step-by-step explanation:
The command that allows you to repair your Windows 10/11 system by checking and fixing corrupted system files is c) System File Checker (SFC). This utility is a part of Microsoft Windows operating systems and is intended to scan and repair system files. To use the System File Checker, you would open an elevated command prompt (running as administrator) and type the command 'sfc /scannow'. The tool will then scan all protected system files and attempt to fix any detected issues. If System File Checker finds a problem that it cannot fix, it will provide details and guidance for additional steps.