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: Pediatrics
[{'content': 'Lactose intolerance in a suspected patient is diagnosed by giving an oral load and measuring concentrations of ? \nSelect and explain. \nA. CO2, B. H2, C. One/two carbon compounds, D. N2', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Hydrogen breath test is used for lactase deficiency and secondary lactose intolerance.', 'role': 'assistant'}]