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
Central dot sign is seen in 
Select and explain. 
A. Primary sclerosing cholangitis, B. Liver Hamaoma, C. Caroli's disease, D. Polycystic liver disease
C: Caroli's disease
Answer: C: Caroli's disease 
Explanation: "central dot" sign: enhancing dots within the dilated intrahepatic bile ducts, representing poal radicles (seen in CT).