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 does not cause biliary tract obstruction ? 
Select and explain. 
A. Ascaris lumbricoides, B. Ankylostoma duodenale, C. Clonorchis sinensis, D. Fasciola hepatia
B: Ankylostoma duodenale
Answer: B: Ankylostoma duodenale 
Explanation: Pathogenesis and clinical features of ankylostoma duodanale Infective agent: filariform larvae Poal of entry: skin The worm causes hookworm disease in man characterized mainly by anaemia. (refer pgno:144 baveja 3 rd edition)