The answer should be B.
When a solid needs to melt, it must absorb enough heat for first, to raise the temperature, and second, to break the bonding. That's why the particles will have a weaker force of attraction to each other. In liquid, the particles will be more free comparing to solid. This type of heat required is called latent heat in specific. It's the heat required to break bonds, or attract bonds when cooling down.
Note that different materials has different specific latent heat for both melting (including freezing) and condensing (including melting).