<prompt> Organism causing billiary duct obstruction:Clonorchis sinensisAnkylostoma duodenaleStrongyloides stercalesEnterobius vermicularis  <response>: Hepatobiliary ParasitismCommon in Southern chinaBiliary tract is infestated by adult helminthes or their ovaCauses :Trematodes Liver or biliary flukes MCClonorchis sinensisOpisthorchis viverrini or O. felineusFasciola hepaticaNematode Ascaris lumbricoides by intraductal migration of adult worm 