As a material transitions from solid to liquid to gas, the correct response about the behavior of the molecules is:
They are going faster because they have more kinetic energy.
In a solid, molecules are closely packed together and vibrate in place, indicating lower kinetic energy. As the solid heats up and transitions to a liquid (melting), the molecules gain energy and start moving more freely, which increases their kinetic energy. When the liquid turns into a gas (vaporization), the molecules gain even more energy and move much faster and farther apart, further increasing their kinetic energy.