You are presented with the quiz "What is one way to lower the freezing point of water?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "adding salt to a solid decreases the freezing point of that solid" and "solutes decrease the freezing point or the point of crystallization of water". 

So, what's the best answer to the question?


 

 add a solute          