Final answer:
The correct answer to the question is that DISM saves changes automatically when running offline changes to an image not part of a VHD file.
Step-by-step explanation:
When running Deployment Image Servicing and Management (DISM) to make offline changes to an image that is not part of a Virtual Hard Disk (VHD) file, the changes are automatically saved. Answering the student's multiple-choice question, the correct option would be: a. Save changes automatically. DISM applies changes as soon as the commands are run successfully, and there's no need to manually save, apply later, or revert the changes unless an error occurs or a specific action is taken by the user to undo the changes.