Which of the following is a common tool used for adjusting mechanical components?

A common tool used for adjusting mechanical components is indeed a wrench. Wrenches are specifically designed to grip and turn nuts, bolts, and other fasteners, which are essential for making adjustments in mechanical assemblies. They come in various types and sizes to accommodate different fastener heads, allowing for flexibility and precision in mechanical adjustments.

While a screwdriver is crucial for fastening screws and a caliper is used primarily for measuring, the wrench's role in adjustments directly impacts mechanical functionality, making it vital for maintenance tasks. Therefore, a well-rounded set of tools including wrenches, screwdrivers, and calipers would indeed cover a broad spectrum of mechanical adjustments, contributing to the decision that all listed tools are valuable in this context.