A Patient with Pneumonia Has Pulmonary Edema

A patient with pneumonia has pulmonary edema.His breathing rate increases,but it can be controlled with oxygen therapy.This is because

A) fluid in the lungs increases the thickness of the respiratory membrane.
B) reduced oxygen will stimulate respiratory rate even if carbon dioxide is normal.
C) a thick respiratory membrane reduces the diffusion rate of oxygen more than the diffusion rate of carbon dioxide.
D) increasing the partial pressure of oxygen in the alveoli will increase the diffusion rate into the alveolar capillaries.
E) All of these are required to construct a complete explanation.