ANSWER
Freezing water
Step-by-step explanation
An exothermic reaction is a type of reaction in which heat is liberated to the surroundings during the reaction.
In an exothermic reaction, the change in enthalpy of the reaction is always negative.
When freezing water to an ice, heat is lost to the surroundings and this type of process is exothermic.
Therefore, the correct answer is freezing water