This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Parasitology Pa 2 (Helminthology), Subject name: Microbiology
[{'content': 'A 45 years male presented with chief complaints of abdominal pain with associated nausea, diarrhea, fatigue, abdominal discomfo, anorexia, weight loss, diarrhea, and jaundice. On imaging of the liver with ultrasound, it shows intra- and extra- hepatic dilatation and strictures with intraductal pigmented stones,What can be the causative agent? \nSelect and explain. \nA. Clonorchis sinensis, B. Enterobius ( Pin worm), C. Strongyloides stercoralis, D. Ancylostoma duodenale', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Parasites which can cause biliary obstruction: Cestodes??" Echinococcus granulosus Trematodes??" Fasciola hepatica, Opisthorchis, Clonorchis sinensis(oriental / chinese liver fluke) Nematodes??" Ascaris lumbricoides', 'role': 'assistant'}]