This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: parasitology, Subject name: Microbiology
Causes of biliary tract carcinoma after ingesting infected fish - 
Select and explain. 
A. Grathostoma, B. Angiostrongylus cantonens, C. Clonorchis sinensis, D. H. Dimunata
C: Clonorchis sinensis
Answer: C: Clonorchis sinensis 
Explanation: In most cases the disease tends to remain low grade and chronic producing only minor symptoms of abdominal distress,intermittent diarrhea and liver pain or tenderness.C.sinensis has been linked to bile duct carcinoma.It is mostly observed in areas where chlonorchiasis is endemic (refer pgno:126 baveja 3 rd edition)