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': 'Best test for esophageal varices is \nSelect and explain. \nA. CT scan, B. Gastroesophagoscopy, C. Tomography, D. Ultrasound', 'role': 'user'}, {'content': 'Answer: B \nExplanation: .', 'role': 'assistant'}]