A technician received a call stating that all files in a user's documents folder appear to be Changed, and each of the files now has a look file extension. Which pf the following actions is the…

Running a live disk clone is a good step for forensic analysis and data recovery, but it should happen after the machine is isolated to prevent further spread of the infection.

Running a full antivirus scan is necessary to identify and remove the ransomware, but it should be done after the machine is isolated from the network to prevent further infection or data exfiltration.

Using a batch file to rename the files will not decrypt them and could potentially complicate recovery efforts by making it harder for decryption tools to identify the original file types.

The described scenario strongly suggests a ransomware attack, where files are encrypted and their extensions are changed. Disconnecting the infected machine from the network immediately is the absolute first step to prevent the ransomware from spreading to other network shares, connected devices, or cloud storage, thus containing the damage.