**Core Concept**
Choledochal cysts are congenital anomalies of the biliary tree, characterized by dilatation of the intrahepatic or extrahepatic bile ducts. This condition often results from an abnormal connection between the biliary tree and the pancreatic duct, leading to bile stasis and potential complications.

**Why the Correct Answer is Right**
The intrahepatic type of choledochal cyst accounts for approximately 5% of cases, whereas the extrahepatic type is more common. The intrahepatic type is often associated with Caroli's disease, a rare congenital disorder affecting the intrahepatic bile ducts. Intrahepatic choledochal cysts can be classified into two types: multiple cysts involving the entire liver (Caroli's disease) or solitary cysts.

**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect as it does not specify the intrahepatic location of the choledochal cyst.
**Option B:** This option is incorrect as it refers to a different biliary condition, choledocholithiasis, which involves the formation of gallstones within the bile ducts.
**Option C:** This option is incorrect as it refers to a different condition, Klatskin tumor, which is a type of cholangiocarcinoma involving the bifurcation of the common hepatic duct.

**Clinical Pearl / High-Yield Fact**
It's essential to differentiate between intrahepatic and extrahepatic choledochal cysts, as the former often requires a different management approach, including surgical resection and potential liver transplantation.

**Correct Answer: D. Intrahepatic choledochal cyst**