This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
Central dot sign is seen in - 
Select and explain. 
A. Caroli's disease, B. Primary sclerosing cholangitis, C. Polycystic liver disease, D. Liver hamartoma
A: Caroli's disease
Answer: A: Caroli's disease 
Explanation: Central Dot sign on CT or USG is seen in:

Caroli's disease (most common cause); 
Prebiliary cysts; 
Obstructive jaundice; and 
Periportal lymphedema.