This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of Gastrointestinal System Including Diarrhea, Subject name: Pediatrics
[{'content': 'The Gold standard investigation for Gastro-Oesophageal reflux disease is: \nSelect and explain. \nA. Endoscopy, B. 24 hour esophageal pH recording, C. Oesophageal manometry, D. Measurement of length of lower oesophageal sphincter', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 24 hour Esophageal pH recording provides a quantitative & sensitive documentation of acidic reflux episodes.', 'role': 'assistant'}]