Which fastening tool uses staples as fasteners?

The tool that uses staples as fasteners is indeed the stapler. A stapler functions by driving metal staples through sheets of material—typically paper—to bind them together securely. The mechanism of a stapler involves either manual pressing or electric activation, whereby the staple's ends are folded over the material, securing it in place.

The other tools mentioned, such as screwdrivers, pliers, and wrenches, serve entirely different purposes, involving screws, gripping or bending materials, and tightening or loosening nuts and bolts, respectively. None of these tools utilize staples in their functioning. Therefore, the stapler stands out as the appropriate tool that utilizes staples as its fastening mechanism.