I believe the change of state shown in the model is deposition.
Deposition is a process in which gases change phase and turns directly in solids without passing through the liquid phase. It is the opposite of sublimation.
One of the major difference between gases and solids is the distance between molecules; in gases the inter molecular spaces are large, while in solid they are very small, making solids be the most dense, with closely packed molecules. This is evident in the diagram, the phase changed from gases to solids.
The answer is the 3rd one down I think
