This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Anatomy
Which investigation is being performed? 
Select and explain. 
A. ERCP, B. MRCP, C. T-tube cholangiography, D. Percutaneous transhepatic Cholangiography
C: T-tube cholangiography
Answer: C: T-tube cholangiography 
Explanation: T-tube seen in the film and a retained CBD stone in the form of a filling defect can be seen in the image.