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': 'IOC for GERD \nSelect and explain. \nA. Endoscopy, B. Barium swallow, C. USG, D. CECT', 'role': 'user'}, {'content': 'Answer: A \nExplanation: IOC for GERD :\xa0endoscopy.', 'role': 'assistant'}]