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
[{'content': 'Which one of the following is not a feature of type 2 respiratory failure ? \nSelect and explain. \nA. p CO2 38 mm Hg and pO2 50 mm HG, B. p CO2 68 mm Hg and pO2 50 mm Hg, C. Papilloedema, D. Asterixis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]