This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Liver), Subject name: Surgery
[{'content': 'A 35 year old male came with jaundice, palpable mass in the right hypochondrium not associated with pain. The probable diagnosis is - \nSelect and explain. \nA. Carcinoma Ampulla of Vater, B. Acute cholecystitis, C. Chronic Cholecystitis, D. Chronic Pancreatitis', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Carcinoma Ampulla of Vater Courvoisier's Lawo Courvoisier's law states that in the presence of an enlarged gall bladder which is nontender and accompanied with jaundice the cause is unlikely to be gallstones. This is because gall stones are formed over a longer period of time, and this result in a shrunken, fibrotic gall bladder which does not distend easilyo In contrast, the gall bladder is more often enlarged in pathologies that cause obstruction of the biliary tree over a shorter period of time such as malignancy of bile duct, pancreas, leading to passive distention from backpressure.", 'role': 'assistant'}]