This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gallstone Disease, Subject name: Surgery
Cause of obstructive jaundice is- 
Select and explain. 
A. Cystic duct stone, B. CBD stone, C. Hepatitis, D. Liver cirrhosis
B: CBD stone
Answer: B: CBD stone 
Explanation: Ans. is 'b' i.e., CBD stone