At equilibrium, which of the following statements is TRUE when helium and nitrogen are present in a gas at equal partial pressures over water?

A) The concentrations of helium and nitrogen in both the water and gas are equal.
B) The concentrations of helium and nitrogen in the water are equal.
C) The concentrations of helium and nitrogen in the gas are equal.
D) The partial pressures of helium and nitrogen in the water are equal.
E) The partial pressure of nitrogen is greater than the partial pressure of helium.