This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Anatomy
[{'content': 'The best test for oesophageal varices is \nSelect and explain. \nA. CT- scan, B. Gastro- oesophagoscopy, C. Tomography, D. Ultrasound', 'role': 'user'}, {'content': "Answer: B \nExplanation: Endoscopy - upper GI endoscopy represents the most reliable single technique as it shows oesophageal varix and bleeding point Dilated longitudinal veins running a Zig- Zag course Diffuse oesophagal spasm is best diagnosed by Manometry Commonest cause of acute upper GI haemorrhage - Peptic ulcer ref - Srb's manual of surgery 5e p790", 'role': 'assistant'}]