uk-dtmh MCQ (SBA): Opisthorchiasis and Cholangiocarcinoma

A 55-year-old woman from rural northeast Thailand presents with right upper quadrant pain and weight loss. CT abdomen reveals an intrahepatic mass suspicious for cholangiocarcinoma. She has a long history of eating raw cyprinoid fish (pla som). Which parasite is most likely to have contributed to her malignancy?