A Popular Classroom Demonstration Is to Place a Gas Can

A popular classroom demonstration is to place a gas can on a burner and boil water in it. Left unchecked this has the potential to be a very boring demo. However the can is removed from the flame and the lid is screwed on tightly. After it cools down the can will

A) still be boring and not change.
B) shrivel up, since colder gases have less pressure.
C) bulge and expand, since colder gases are denser and exert more pressure
D) shrivel up, since the atmosphere exerts more force on the can as it cools.