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: Unknown
The risk factor in cholangiocarcinoma - 
Select and explain. 
A. Pancreatitis, B. Caroli disease, C. Pyelonephritis, D. Ulcerative colitis
B: Caroli disease
Answer: B: Caroli disease 
Explanation: Ans. is 'b' i.e., Caroli disease Cholangiocarcinoma o Cholangiocarcinoma is a malignancy of the biliary tree, arising from bile ducts within or outside the liver, o Risk factors All risk factors for cholangiocarcinomas cause chronic inflammation and cholestasis, which presumably promote the occurrence of somatic mutations or epigenetic alterations in cholangiocytes. Primary sclerosing cholangitis. Hepatolithiasis. Congenital fibro-polycystic disease of the biliary system (Caroli disease, choledochal cyst). Hepatitis B and C. Exposure to thorotrast. Opisthorchissinensis and clonorchiasis infection.