How is specific latent heat of fusion defined?

Specific latent heat of fusion is defined as the energy required to change a solid into a liquid at its melting point without a change in temperature. This process involves breaking the bonds that hold the molecules in the solid structure together, which requires energy. The term "specific" refers to the amount of energy per unit mass; hence, it specifies the energy needed for a given mass of the substance. This is why the correct choice clearly states the energy per unit mass to change a solid to a liquid, emphasizing both the state change and the measurement per unit mass involved.