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': 'What is the most appropriate for diagnosis of CBD stones \nSelect and explain. \nA. Ultrasonography, B. ERCP, C. OCG, D. IV cholangiography', 'role': 'user'}, {'content': 'Answer: B \nExplanation: USG : first test, can document GB stones and estimate the CBD diameter A dilated bile duct (>8mm in diameter) in a patient with gallstones, jaundice and biliary pain is highly suggestive of choledocholithiasis MRCP : Provides excellent anatomic detail with sensitivity and specificity of 95 %and 98 %, respectively, for CBD stones ERCP : Diagnostic and therapeutic test of choice for patients with suspected CBD stones Ref: Sabiston 20th edition Pgno :1494', 'role': 'assistant'}]