Answer: Option (B) is the correct answer.
Step-by-step explanation:
Heat of fusion is defined as the heat energy required to convert a solid substance in liquid state.
So, when we heat a solid substance then the heat absorbed by it helps in breaking of intermolecular forces of attraction. As a result, solid substance will start to melt and during this change the temperature remains constant until the substance completely melts which is known as latent heat of fusion.
Hence, we can conclude that the temperature of a substance remains constant as its heat of fusion is added to melt the substance.