Which of the following wrenches is specifically for fastening and loosening plumbing fittings?

The choice of a pipe wrench for fastening and loosening plumbing fittings is correct because pipe wrenches are specifically designed to grip and turn cylindrical objects, primarily pipes. The pipe wrench features a serrated jaw that provides a strong grip on the surface of the pipe without slipping, allowing the user to apply significant torque. This is particularly important in plumbing applications, where fittings and pipes may be tightly threaded or sealed.

In contrast, socket wrenches are typically used for fastening and loosening bolts and nuts, which have a different shape and require a different method of engagement. Torque wrenches are designed to apply a specific amount of torque to a fastener, ensuring that it is tightened to the correct specifications, but they are not specialized for plumbing fittings. Box wrenches can grasp fasteners like nuts and bolts but do not provide the unique design features necessary for the round shapes of pipes. Thus, the pipe wrench stands out as the appropriate tool for plumbing tasks.