mixing salt and pepper melting butter stirring salt into water melting an ice cube
I gave my students this multiple choice question: Louisa needs to demonstrate a solution to her class. Which is the best example of a solution?

Only one answer is correct among these 4 choices:
- mixing salt and pepper
- melting butter
- stirring salt into water
- melting an ice cube

Could you tell me which one is correct?

stirring salt into water