Answer:
A-L
Explanation:
Since before the change, the substance is described as having atoms "close together" and "cannot slide past one another", one can assume this is a solid, since in both liquids and gases, the atoms can move around more or less freely.
Then, it explains that the new substance "can fill a container", which is a property of both a liquid and a gas.
Thus, the answer would be either P, solid to liquid, or L, solid to gas.
Since P is not an option you can choose, by process of elimination, that leaves L, or option A.
Have a nice day! ^-^
