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: Anatomy
Choledochal cyst in intrahepatic biliary tree 
Select and explain. 
A. I, B. II, C. IVa, D. IVb
C: IVa
Answer: C: IVa 
Explanation: Todani Modification of Alonso-Lej classification Type I - Dilation of extrahepatic biliary tree Type Ia- cystic dilation Type Ib - focal segmental dilation Type Ic- fusiform dilation Type II - Diveicular dilation of extrahepatic biliary tree Type III - Cystic dilation of intra duodenal poion of common bile ducts (choledochocele) Type IVA- Dilation of the extrahepatic and intrahepatic biliary tree Type IVB- Dilation of multiple secretion of extrahepatic bile ducts Type V - Dilation confined to intrahepatic bile ducts (caroli's disease) Type VI - Cystic dilation of cystic duct (not included in Todani's modification) Ref: Sabiston 20th edition Pgno :1510-1511