Which of the Following Statements Is Correct

Which of the following statements is correct?

A) At the melting point of a substance, the solid, liquid, and gas phases are all in equilibrium.
B) The freezing point and the melting point of a substance are the same.
C) There is no fundamental difference in the melting process for covalent substances and ionic substances.
D) When iodine vapor cools at atmospheric pressure, it condenses to the liquid state.
E) In order for a substance to go from the liquid phase to the gas phase, it must give off energy to the surroundings.