<prompt> Which is risk factor for cholangiocarcinomaObesityPrimary sclerosing cholangitisSalmonella carrier stateHBV infection  <response>: Risk factors include primary sclerosing cholangitis Congenital fibropolycystic disease of biliary tree Infestation by Clonorchis sinensis or Opisthorchis viverrini HCV infection Exposure to Thorotrast TEXT BOOK OF ROBBINS BASIC PATHOLOGY NINTH EDITION PAGE.643 