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
Ioc in Choledocholithiasis 
Select and explain. 
A. USG, B. MRCP, C. ERCP, D. HIDA Scan
B: MRCP
Answer: B: MRCP 
Explanation: IoC for Cholelithiasis - USG
IoC for Choledocholithiasis - MRCP.