This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gall Bladder & Bile Ducts, Subject name: Surgery
Risk factors of gallbladder carcinoma are all except 
Select and explain. 
A. Gallbladder Polyps, B. Typhoid carriers, C. Exposure to carcinogens like nitrosamine, D. Echinococcus Granulosus Infection
D: Echinococcus Granulosus Infection
Answer: D: Echinococcus Granulosus Infection 
Explanation: Ans. (d) Echinococcus Granulosus infectionRef: Bailey 26th edition Page 1116Risk factors of cancer GB:* Gallstones* Polyps * Porcelain GB* Choledochal cyst* Anomalous pancreato bile duct junction* Typhoid carriers* Sclerosing cholangitis* Ulcerative colitis* Cholecysto enteric fistula* Drugs- estrogens * Carcinogens