Answer: A) Atoms gain energy as a solid changes to a liquid.
Explanation: Atoms in liquid possess more energy than the atoms in solid. The change of state from a solid state to a liquid state is called melting. Energy is applied to the molecules in solid state the molecules begin to move quicker and begins to break away from the other molecules. The heat absorbed leads to the molecules to moving farther apart from others thereby overcoming the intermolecular forces of attraction between them.
The solid state gains energy in form of heat as solids converts to liquid.
