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
Investigation of choice in acute cholecystitis 
Select and explain. 
A. OCG, B. HIDA scan, C. USG, D. CT
C: USG
Answer: C: USG 
Explanation: Investigation of choice for acute cholecystitis : USG Gold standard for diagnosis of acute cholecystitis : HIDA scan USG is investigation for acute calculous cholecystitis, chronic cholecystitis and cholelithiasis Ref: Sabiston 20th edition Pgno :1493