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: Unknown
[{'content': 'Which of the following defines ARDS all except ? \nSelect and explain. \nA. PaO2/FiO2<300, B. Acute onset, C. Bilateral alveolar infiltrates, D. PCWP>18 mm Hg', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ref. API Textbook of Medicine. Pg. 259', 'role': 'assistant'}]