As a scuba diving air tank is filled with air, the air is compressed in the tank to as much as 3000 psi of pressure. When filling the tank, it is observed that the tank becomes warmer.

Which argument BEST explains why this occurs?

A
When air is compressed, it turns solid. A short time later, the air evaporates back into a gas which releases heat.
B
When air is compressed, the molecules line up into a crystalline structure. As the molecules line up, they release energy in the form of heat.
C
When air is put into the tank, it expands rapidly, thereby raising the temperature.
D
Air molecules are free to move and as more air is added to the tank, the molecules move and collide faster which raises the temperature.