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: Surgery
Saccular diveiculum of extrahepatic bile duct in choledochal cyst is classified as 
Select and explain. 
A. Type I, B. Type II, C. Type III, D. Type IV
A: Type I
Answer: A: Type I 
Explanation: Type 1b -saccular dilatation of extrahepatic biliary tree, Type 2-diveiculum of extrahepatic biliary tree Type 3-cystic dilatation of intraduodenal pa of CBD Type 4- dilatation of multiple pas of an extrahepatic biliary tree, dilatation of intrahepatic and extrahepatic biliary tree. Reference SRB edition 5. page637