Which of the following may cause biliary obstruction:

Clonorchis sinensis is a liver fluke. Cysts of this organism is consumed and larvae develop in the duodenum and eventually reach the biliary tree where it cause obstruction with complicating suppurative cholangitis and cholangiocarcinoma. Clonorchis sinensis is an established cause of biliary obstruction. Ref: Diseases of the Liver and Biliary System By Sheila Sherlock, Sheila Sherlock (Dame), James S. Dooley, Page 518; Harrison's Principles of Internal Medicine, 17th Edition, Page 1334, 1335.