Which statement about hex bolts is true?

Hex bolts are versatile fasteners commonly used in construction and mechanical applications, and they come in a variety of sizes. The assertion that they can range in diameter and length reflects their design, which accommodates different needs for strength and load-bearing capacity. This variety allows for the selection of a hex bolt that fits specific requirements for a project, making them suitable for an extensive range of applications.

While some bolts might be available in fixed lengths or diameter specifications, this is not a limitation of hex bolts. They can be found in various lengths and diameters, enabling users to choose the appropriate bolt for a given job. This adaptability is one of the significant advantages that hex bolts offer in the realm of hardware.

The other options present limitations or inaccuracies about hex bolts that do not align with their characteristics. For instance, stating that they only come in fixed lengths incorrectly narrows their usability, while claiming they are designed solely for soft metals is a misconception that overlooks their application in many materials, including hard metals. Lastly, the comparison to carriage bolts fails to recognize the distinct features and uses of each type of bolt.