This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gall Bladder & Bile Ducts, Subject name: Surgery
A patient presented with Right upper quadrant pain with dyspepsia. USG showed Edematous Gallbladder wall. What will be the most sensitive investigation to confirm the suspected diagnosis here? 
Select and explain. 
A. CECT, B. HIDA, C. MRI, D. ERCP
B: HIDA
Answer: B: HIDA 
Explanation: Ans. (b) HIDA scanRef Sabiston Page 1488/20th edition* Gold standard investigation for Acute Cholecystitis- HIDA scan* Finding- Non visualization of Gallbladder in HIDA Scan