What does latent heat of fusion refer to?

Latent heat of fusion refers to the amount of heat energy required to change a substance from a solid to a liquid at its melting point, without changing its temperature. When it comes to water, the latent heat of fusion specifically describes the process of ice melting into water. During this phase change, heat is absorbed by the ice, allowing it to overcome the molecular forces holding it in a solid structure, thereby transforming into liquid water.

None of the other options accurately represent the definition of latent heat of fusion. For example, the conversion of water to steam relates to the latent heat of vaporization, which deals with the phase change from liquid to gas. Similarly, the transformation of ice to water is the direct application of the latent heat of fusion, and hence is the correct interpretation of the term.