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
Focal and diffuse thickening of gallbladder wall with high amplitude reflections and 'comet tail' artifacts on USG suggest the diagnosis of – 
Select and explain. 
A. Xanthogranulomatous cholecysitis, B. Carcinoma of gall bladder, C. Adenomyomatosis, D. Cholesterolosis
C: Adenomyomatosis
Answer: C: Adenomyomatosis 
Explanation: Focal and diffuse thickening of gallbladder wall with comet tail artifact is characteristic of adenomyomatosis of the gallbladder.