Concept:Melting is a change of state in which a solid absorbs heat but the temperature stays constant during the actual process of melting.
Explanation:For a solid to change into a liquid, heat energy must be supplied to it.
Before melting begins, the temperature of the solid rises continuously as it absorbs heat.
When the melting point is reached, the temperature of the solid becomes steady and remains constant throughout the melting process.
The heat supplied at this stage is not used to increase the temperature, it is used to weaken the intermolecular forces holding the particles together.
Once the entire solid has melted into liquid, further heating causes the temperature to rise again.
Therefore, the temperature of the solid rises before melting, remains constant during melting, and rises again after melting.
Answer:C. I, II and III only