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: Pathology
[{'content': "Adeno carcinoma of gall bladder are always located in -a)  Fundusb)  Neckc) Hartmann's pouchd)  Bile duct \nSelect and explain. \nA. ac, B. a, C. ad, D. ab", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Carcinoma of Gall bladder\n\nCarcinoma of gall bladder are adenocarcinoma.\nThe most cammon sites of involvement are the fundus and the neck, about 20% involve the lateral walls.\nThere are two growth patterns.\n\t(i) \xa0Infiltrating-more common\n\t(ii)\xa0Exophytic', 'role': 'assistant'}]