What basic tool is often carried in the cab of a grader for minor repairs?

A wrench set is an essential tool that is commonly kept in the cab of a grader for performing minor repairs. This is because graders, like many heavy machinery, experience wear and tear on various components that may require adjustments or tightens from time to time. Wrenches are versatile tools that allow operators to quickly address issues such as loose bolts or components on the grader, ensuring the machine operates efficiently and safely.

In the context of the other choices, while a screwdriver set has its uses, it is more suited for adjustments that involve screws rather than the bolts and nuts common in heavy machinery like graders. A measuring tape, while useful for tasks requiring precision measurements, does not serve the purpose of immediate repairs. A crowbar, though potentially helpful for prying apart components, is less commonly needed for standard operational repairs on a grader. Hence, the wrench set stands out as the most practical and frequently utilized tool for the maintenance and functionality of the grader.