You are presented with the quiz "Which action will cause chemical bonds to form?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "chemical bonds form when substances react with one another" and "vinegar and baking soda, when mixed together, react chemically to create carbon dioxide gas". 

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


 

    Mixing baking soda and vinegar       