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
Which of the following may cause biliary obstruction - 
Select and explain. 
A. Ancylostoma, B. Entrobius, C. Strongyloides, D. Clonorchis
D: Clonorchis
Answer: D: Clonorchis 
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 clonorchiasis is endemic (refer pgno:126 baveja 3 rd edition)