Which of the following best describes malleability?

Malleability refers specifically to the physical property of materials, especially metals, that allows them to be deformed under compressive stress. This means that a malleable material can be hammered, rolled, or pressed into various shapes without breaking or fracturing. The definition aligns perfectly with the ability of a solid to be hammered without shattering, which reflects the inherent ductility and flexibility of the material when subjected to force.

In contrast, the other options describe different properties: the first option pertains to electrical conductivity, which is not related to malleability at all. The third option discusses solubility, focusing on a material's ability to dissolve, which is irrelevant to its mechanical properties. The fourth option, involving the change of state from solid to liquid, deals with phase changes rather than the physical deformation characteristics of solids. Thus, the best description of malleability is indeed the ability of a solid to be hammered without shattering.