Ans. is 'd' i.e., Oral contraceptives No risk of Ca G.B. has been noted with the use of oral contraceptiveso Risk factors for Ca Gall bladder are :i) Gall stonesApproximately 90% of patients with Ca GB have gall stonesSize of the stone has a direct relationship with development of carcinoma, the risk is ten times more for larger stones (3 cm in diameter) than for stones less than 1 cm in diameterThe risk is higher with symptomatic than asymptomatic stones.ii) Adenomatous gall bladder polyps (particularly polyps larger than 10 mm)Calcified (porcelain) gall bladderCholeduochal cystEstrogensAnomalous pancreaticobiliary duct junctionExposure to carcinogens (azotoulene, nitrosamine)Typhoid carriersSclerosing cholangitisCholecystoenteric fistula Ulcerative colitis o ASI Surgery mentions two other risk factorsChemicals used in rubber industryUse of adulerated mustard cooking oil in India