Final answer:
The proper distance between the tool rest and the wheel on a bench grinder is 1/8 inch to ensure safety and proper operation.
Step-by-step explanation:
The correct distance between the tool rest and the wheel on a bench grinder should be 1/8 inch (Option B). This is crucial to ensure safety and effectiveness when using the bench grinder. If the gap is too large, there is a risk that workpieces may become lodged between the wheel and the rest, potentially causing injury or damaging the workpiece and the wheel. Conversely, if the tool rest is too close, it may interfere with the operation of the grinder. Keeping the proper distance helps in maintaining the stability of the workpiece during grinding and in preventing accidents.