I say B because the gallbladder is part of the biliary tract, which produces bile, and the gallbladder hold that bile until it needed to digest fatty foods in the duodenum, which is the first part of the small intestine immediately beyond the stomach. Gallstones can either be a single stone to hundreds of tiny ones. These gallstones block the biliary ducts and the bile starts to accumulate around the body. Cholecystitis makes it worse by inflaming the gallbladder causing disorders in the liver, and since the body can't digest the fatty foods the person won't have a appetite, which will cause a rapid weight decrease.