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': 'The gold standard investigation for Gastro-esophageal reflux disease is \nSelect and explain. \nA. Endoscopy, B. 24 hour ph recording, C. Oesophageal manometry, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 24 hour ph\xa0monitoring of distal esophagus provides quantitative sensitive documentation of acidic reflux episodes.', 'role': 'assistant'}]