Final answer:
To prevent users from editing files in 'C:\ Files', set NTFS permissions to read only. This ensures users can view but not alter the contents. Other options like setting the owner or changing index settings do not restrict editing permissions.
Step-by-step explanation:
In order to prevent other users from editing files in the 'C:\ Files' directory, the correct step would be to Set NTFS permissions to read only. NTFS permissions are used to control access to files and folders in Windows operating systems. By setting these permissions to read-only, you ensure that users can view the files, but cannot modify, delete, or add new files in the folder.
Setting the folder to index files for search or changing the owner of the folder to a local administrator does not directly restrict editing permissions. Similarly, setting network share permissions to read-only affects the files over the network, but not the local editing permissions. Therefore, the direct and effective approach to prevent editing is to modify the NTFS permissions.