Which statement best explains this occurrence?

As pressure in a closed container is increased, the volume, or amount of space that a gas takes up, decreases. Divers who work underwater use tanks containing oxygen in order to breathe. The amount of oxygen in the tanks allows the divers to stay underwater for some time, yet the tanks are not huge.

Which statement best explains this occurrence?
A . Oxygen has to be in small metal tanks so that divers don’t sink.
B . Oxygen takes up only a small amount of the air that we breathe.
C . If the tanks are small, the fish will not be frightened by the divers.
D . Since the oxygen is under pressure, a large amount of oxygen can be placed in these small tanks.
E . Most divers don’t stay underwater for a very long time because they get very cold quickly.

Answer: D