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: Radiology
[{'content': 'Gastro-oesophageal reflux is best detected by \nSelect and explain. \nA. Endoscopy, B. USG, C. Barium study, D. Isotope scan', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Endoscopy - G-O-Reflux is best diagnoses by 24 hours Acid studyQ & the next best investigation is EndoscopyQ. - 24 hours PH recording (Acid StudyQ) is the gold standerd for GOR diagnosis.', 'role': 'assistant'}]