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': "Focal and diffuse thickening of gallbladder wall with high amplitude reflections and 'comet tail' artifacts on USG suggest the diagnosis of – \nSelect and explain. \nA. Xanthogranulomatous cholecysitis, B. Carcinoma of gall bladder, C. Adenomyomatosis, D. Cholesterolosis", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Focal and diffuse thickening of gallbladder wall with comet tail artifact is characteristic of adenomyomatosis of the gallbladder.', 'role': 'assistant'}]