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
Which of the following statements about acute cholecystitis is true? 
Select and explain. 
A. It usually occurs due to obstruction at the neck of gall bladder, B. On HIDA scan. gall bladder is not visualized, C. Immediate cholecystectomy can never be done, D. Analgesics and intravenous fluids are the best treatment
B: On HIDA scan. gall bladder is not visualized
Answer: B: On HIDA scan. gall bladder is not visualized 
Explanation: Ans.On HIDA scan. gall bladder is not visualized