This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oncology, Subject name: Medicine
The following are risk factors for developing cholangiocarcinoma except - 
Select and explain. 
A. Choledochal cyst, B. Cholelithiasis, C. Liver flukes, D. Working in the rubber industry
D: Working in the rubber industry
Answer: D: Working in the rubber industry 
Explanation: Cholangiocarcinoma (CCA) is an uncommon tumour that can arise anywhere in the biliary tree, from the intrahepatic bile ducts (20-25% of cases) and the confluence of the right and left hepatic ducts at the liver hilum (50-60%) to the distal common bile duct (20%). It accounts for only 1.5% of all cancers but the incidence is increasing. The cause is unknown but thetumour is associated with gallstones, primary and secondary sclerosing cholangitis, Caroli's disease and choledochal cysts . ref Harrison 20th edition pg 567