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: Pathology
Cholangio carcinoma of liver caused by 
Select and explain. 
A. Hepatitis B infection, B. Cirrhosis of liver, C. Alpha - feto protein, D. Clonorchis sinensis infection
D: Clonorchis sinensis infection
Answer: D: Clonorchis sinensis infection 
Explanation: risk factor of cholangio carcinoma includes Primary sclerosis cholangitis Fibropolypocystic disease of biliary tree Infestation by Clonorchis sinensis or Opisthorchis viverrini. ROBBINS BASIC PATHOLOGY NIanTH EDITION PAGE 643