This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Body composition and Acid base Balance, Subject name: Pediatrics
[{'content': 'Respiratory acidosis is characterized by primary: \nSelect and explain. \nA. Deficit of carbonic acid, B. Excess of carbonic acid, C. Deficit of bicarbonate, D. Excess of bicarbonate', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Respiratory acidosis is caused by CO2 retention - excess carbonic acid.', 'role': 'assistant'}]