Concept:The heat absorbed during melting is latent heat of fusion, used to overcome intermolecular forces rather than raise temperature.
Explanation:At the melting point, a solid changes to liquid at constant temperature.
The supplied heat increases the internal potential energy of the molecules, not their kinetic energy.
This energy is consumed in breaking the bonds holding the molecules firmly together in the solid lattice.
Once the bonds are weakened enough to allow free movement, the substance is fully liquid.
Only after complete melting does further heat supply cause the temperature to rise.
Answer:A. All the heat is used to break the bonds holding the molecules of the solid together.