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: Surgery
[{'content': 'Most useful investigation in sliding hernia in female - \nSelect and explain. \nA. Fluoroscopy, B. Barium-meal, C. Palpation method, D. Ultrasound', 'role': 'user'}, {'content': 'Answer: B \nExplanation: • The hernia may be visible on a plain radiograph of the chest as a gas bubble, often with a fluid level behind the heart.\n• A barium meal is the best method of diagnosis.\n• The endoscopic appearances may be confusing, especially in large hernias when it is easy to become disorientated.', 'role': 'assistant'}]