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': 'Best investigation for acute cholecystitis is \nSelect and explain. \nA. ERCP, B. Oral cholecystography (OCG), C. HIDA scan, D. IV cholangiography', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. HIDA Scan HIDA Scan & PIPIDA are best test to rule out acute cholecystitisQ with.--400% negative predictive value. It can be pseudo positive in chronic malnutrition, & Parenteral nutrition & alcoholic liver disease.', 'role': 'assistant'}]