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': 'Acalculous cholecystitis is caused by all except \nSelect and explain. \nA. DM, B. TPN, C. Leptospirosis, D. Estrogen therapy', 'role': 'user'}, {'content': "Answer: D \nExplanation: Causes of Acalculous cholecystitis Common causes Elderly and critically ill patients after trauma Burns Longterm TPN Major operations(Abdominal aneurysm repair and cardiopulmonary bypass) Diabetes mellitus Uncommon causes Vasculitis Obstructing GB adenocarcinoma GB torsion Parasitic infestation Unusual bacterial infection - Leptospira, streptococcus, salmonella , Vibrio cholera Ref: Harrison's 19th edition Pgno : 2081", 'role': 'assistant'}]