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': 'Investigation of choice in obstructive jaundice is \nSelect and explain. \nA. ERCP, B. USG, C. Cholecystography, D. Laproscopy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. USG', 'role': 'assistant'}]