The molecules :

1. in solid, liquid and gas, move freely anywhere.
2. in a solid, move freely within its boundary.
3. in a liquid, move within its boundary.
4. in a gas, move only within its boundary.

in a liquid, move within its boundary.

Reason — The molecules in a solid are fixed at their positions and can only vibrate about their mean positions while in a liquid they can move within the boundary and moves freely in space in gas.