The wrench best suited for the final tightening of a nut is __________.

• A. Open-end wrench
• B. Box-end wrench
• C. Adjustable wrench
• D. Socket wrench

Answer: (B)

When you’re aiming to finish tightening a nut securely, you want grip and control that prevent slipping and rounding of the fastener. A box-end wrench delivers that by around-the-nut contact: its head surrounds the nut and engages all sides, so torque is applied evenly and the corners are protected from damage. This enclosing grip means you can apply higher, steadier torque with less risk of the wrench popping off or chewing the edges of the nut.

Open-end wrenches only contact two faces and are more prone to slipping if not perfectly aligned, which can round the nut. An adjustable wrench has jaws with some play, so it can slip and mar the fastener under high torque. A socket wrench is versatile and strong, but for final tightening where maximum engagement and protection against rounding are paramount, the box-end’s full encirclement of the nut makes it the better choice.