Final answer:
The maximum distance between the work rest and the wheel for grinding wheels is at least 10 inches to ensure safety and effective grinding.
Step-by-step explanation:
The maximum distance between the work rest and the wheel depends on the safety guidelines provided. In the case of grinding wheels, newer recommendations suggest a distance of as much as 8 diameters of the wheel side-to-side and 15 diameters deep. So, the answer would be option 2: At least 10 inches. This ensures that the workpiece is safely supported and the grinding process can be carried out effectively.