Which Statement Best Describes Why the Law of Mass Action

Which statement best describes why the law of mass action explains the loading and unloading of oxygen in hemoglobin?

A) The mass of both carbon dioxide and oxygen is the same and therefore they exchange at the same rates
B) Oxygen has a greater mass than carbon dioxide and therefore can load more quickly than carbon dioxide.
C) As oxygen levels in the pulmonary capillaries decrease, more carbaminohemoglobin is formed due to the concentration of carbon dioxide.
D) As oxygen level rises, so does the pressure, which breaks the bonds of hemoglobin thereby releasing hemoglobin to the tissues.
E) As oxygen levels in the pulmonary capillaries increase, more oxyhemoglobin is formed. Conversely, as oxygen levels in the systemic capillaries decrease, the reaction reverses and releases oxygen from hemoglobin.