Which is true regarding the oxygen content of air?

A)It is less than the oxygen dissolved in an equal volume of water.
B)It is equal to the oxygen content of an equal volume of water at the same pressure.
C)It is 20 times greater than in an equal volume of water.
D)It is irrelevant to the animal lung since it must still diffuse across the wet surface of membranes.
E)It is approximately 1000 times greater than in an equal volume of water.