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': 'pH 7.24, PaO2 55 mm Hg, PaCO2 55 mm Hg, HCO3 - 30 mEq/L consistent with - \nSelect and explain. \nA. Respiratory acidosis, B. Respiratory alkalosis, C. Metabolic acidosis, D. Metabolic alkalosis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]