This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Which one of the following distinguishes ARDS (acute/adult respiratory distress syndrome) from cardiogenic pulmonary oedema ? 
Select and explain. 
A. Normal PaO2, B. Normal pulmonary arterial pressure, C. Normal arterial-alveolar gradient, D. Normal PaCO2
B: Normal pulmonary arterial pressure
Answer: B: Normal pulmonary arterial pressure 
Explanation: None