The correct answer to the question is : Chemical energy
Step-by-step explanation:
As per the question, an icepack of ammonium nitrate is dissolved in water.
The reaction of ammonium nitrate with water is an endothermic reaction. It means that heat is absorbed during this chemical reaction in order to initiate the chemical reaction.
As this reaction is an endothermic reaction, the temperature of the mixture is decreased. The energy absorbed in this process has been utilized in the formation of new compounds, and is stored in the form of chemical energy.
Hence, the heat energy is converted into chemical energy.