The answer is...Liquid into gas.
My Explanation:
Stated in the model, The atoms aren't that active but can still slider past each other; meaning, this is a liquid. As it shifts into a gas, which is when atoms pick up energy and move around more freely/actively, the definition of the following is "Vaporization".
So the answer is: B, or in other words, "Atoms gain energy as a liquid turns into a gas.
